code_mirror: move editor field's inline css to separate file

This was not valid HTML5:

  AssertionError: Using nu validator to parse the view "SQLMethod_view" (from erp5_core bt) with warnings displayed :
  Error: line 782 column 23 : Element “style” not allowed as child of element “div” in this context. (Suppressing further errors from this subtree.): </script>
  <style type="text/css">
    .cm
  Error: line 822 column 23 : Element “style” not allowed as child of element “div” in this context. (Suppressing further errors from this subtree.): script>

  <style type="text/css">
    .max

bt5/erp5_code_mirror/SkinTemplateItem/portal_skins/erp5_code_mirror/code_mirror_support.txt

 <script type="text/javascript" src="&dtml-portal_url;/codemirror/lib/codemirror.js"></script>
 <link rel="stylesheet" href="&dtml-portal_url;/codemirror/lib/codemirror.css">
+<link rel="stylesheet" href="&dtml-portal_url;/erp5-codemirror.css">
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/mode/&dtml-mode;/&dtml-mode;.js"></script>
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/addon/cm_edit/matchbrackets.js"></script>
 
 <!-- Trailing spaces -->
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/addon/cm_edit/trailingspace.js"></script>
-<style type="text/css">
-  .cm-trailingspace {
-    background-color: gray;
-  }
-</style>
 
 <!-- Search addons -->
 <link rel="stylesheet" href="&dtml-portal_url;/codemirror/addon/dialog/dialog.css">
@@ -63,72 +59,6 @@
 <script type="text/javascript" src="&dtml-portal_url;/codemirror/mode/css/css.js"></script>
 </dtml-if>
 
-<style type="text/css">
- .maximize_fullscreen_message {
-   display: table;
-   position: absolute;
-   bottom: 0;
-   right: 20px;
-   max-width: 40%;
-   z-index: 424242;
-   padding: 10px;
-   background-color: #DAE6F6;
-   border: 1px solid #97B0D1;
-   opacity: 0.3;
-   cursor: pointer;
-   font-weight: bold;
- }
-
- .maximize_fullscreen_error_message {
-   background-color: red;
- }
-
- .maximize_fullscreen_message > div {
-   font-size: 14px;
-   display: table-cell;
-   vertical-align: middle;
- }
-
- #maximize_message {
-   display: block !important;
-   position: absolute !important;
-   bottom: 0 !important;
-   right: 0px !important;
-   z-index: 4243 !important;
-   padding: 10px;
-   font-size: 16px;
-   font-weight: bold;
-   background-color: black;
-   color: white;
- }
-
- .maximize {
-   position: fixed;
-   right: 0;
-   bottom: 0;
-   top: 0 !important;
-   left: 0 !important;
-   z-index: 2 !important;
-   overflow: hidden !important;
- }
-
- .CodeMirror pre, .CodeMirror span {
-   font-family: monospace !important;
- }
-
- /* Workaround for lint icons "multiple" icons hiding "warning/errors" icons
-    because of "background-color: inherit" defined by erp5, and also to fix
-    background color of the gutter (cosmetic) */
- .CodeMirror-lint-marker-multiple,
- .CodeMirror-lint-marker-error,
- .CodeMirror-lint-marker-warning,
- .CodeMirror-gutters,
- .CodeMirror-gutter-elt,
- .CodeMirror-sizer,
- .CodeMirror-line {
-   background-color: transparent !important;
- }
-</style>
 
 <!-- TODO: Only supported for ZODB Components -->
 <dtml-unless bound_names>

bt5/erp5_code_mirror/SkinTemplateItem/portal_skins/erp5_code_mirror/erp5-codemirror.css.css

+/* trailing spaces */
+.cm-trailingspace {
+  background-color: gray;
+}
+
+/* full screen/maximize */
+.maximize_fullscreen_message {
+  display: table;
+  position: absolute;
+  bottom: 0;
+  right: 20px;
+  max-width: 40%;  
+  z-index: 424242;
+  padding: 10px;
+  background-color: #DAE6F6;
+  border: 1px solid #97B0D1;
+  opacity: 0.3;
+  cursor: pointer;
+  font-weight: bold;
+}
+.maximize_fullscreen_error_message {
+  background-color: red;
+}
+.maximize_fullscreen_message > div {
+  font-size: 14px;
+  display: table-cell;
+  vertical-align: middle;
+}
+#maximize_message {
+  display: block !important;
+  position: absolute !important;
+  bottom: 0 !important;
+  right: 0px !important;
+  z-index: 4243 !important;
+  padding: 10px;
+  font-size: 16px;
+  font-weight: bold;
+  background-color: black;
+  color: white;
+}
+.maximize {
+  position: fixed;
+  right: 0;
+  bottom: 0;
+  top: 0 !important;
+  left: 0 !important;
+  z-index: 2 !important;
+  overflow: hidden !important;
+}
+
+.CodeMirror pre, .CodeMirror span {
+  font-family: monospace !important;
+}
+
+/* Workaround for lint icons "multiple" icons hiding "warning/errors" icons
+because of "background-color: inherit" defined by erp5, and also to fix
+background color of the gutter (cosmetic) */
+.CodeMirror-lint-marker-multiple,
+.CodeMirror-lint-marker-error,
+.CodeMirror-lint-marker-warning,
+.CodeMirror-gutters,
+.CodeMirror-gutter-elt,
+.CodeMirror-sizer,
+.CodeMirror-line {
+  background-color: transparent !important;
+}

bt5/erp5_code_mirror/SkinTemplateItem/portal_skins/erp5_code_mirror/erp5-codemirror.css.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="File" module="OFS.Image"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>_Cacheable__manager_id</string> </key>
+            <value> <string>http_cache</string> </value>
+        </item>
+        <item>
+            <key> <string>__name__</string> </key>
+            <value> <string>erp5-codemirror.css</string> </value>
+        </item>
+        <item>
+            <key> <string>content_type</string> </key>
+            <value> <string>text/css</string> </value>
+        </item>
+        <item>
+            <key> <string>precondition</string> </key>
+            <value> <string></string> </value>
+        </item>
+        <item>
+            <key> <string>title</string> </key>
+            <value> <string></string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>