software/theia: Make theiaN frontend names unique

This concerns a case of resiliency in Theia: when a resilient Theia
requests multiple import clones (by default only one is requested),
e.g. when theia0 (export) has two import clones theia1 and theia2.

Each clone requests a frontend for their theia service, which allows
the Theia editor of the clone to be accessed without doing a takeover.

Before this, all the import clones would request a frontend with the
same name. This meant that only one frontend was allocated and might
randomly redirect to one of the backup clones.

See merge request nexedi/slapos!1481

software/theia/buildout.hash.cfg

@@ -23,7 +23,7 @@ md5sum = 9658a11340c018de816d0de40683706a
 
 [instance-import]
 _update_hash_filename_ = instance-import.cfg.jinja.in
-md5sum = 6520d2aa0c1c6094cbf276080594ec1a
+md5sum = c8d1be7aee980deb0f0d1a3126c9b9da
 
 [instance-export]
 _update_hash_filename_ = instance-export.cfg.jinja.in

software/theia/instance-import.cfg.jinja.in

 {%- set parameter_dict = dict(default_parameter_dict, **parameter_dict) -%}
 {%- set additional_frontend = parameter_dict['additional-frontend-guid'] -%}
+{%- set namebase = parameter_dict['namebase'] -%}
+{%- set theia_number = parameter_dict['number'] -%}
+{%- set theia_id = '%s%s' % (namebase, theia_number) -%}
+{%- set frontend_name = parameter_dict['frontend-name'] -%}
 
 [buildout]
 extends = {{ theia_instance_cfg }}
@@ -16,16 +20,16 @@ parts +=
 # The import template then expects to receive it in
 # slap-parameter:namebase
 [slap-parameter]
-namebase = {{ parameter_dict['namebase'] }}
+namebase = {{ namebase }}
 
 
 # Change frontend name to avoid conflicts
 [remote-frontend]
-name = Import {{ parameter_dict['frontend-name'] }}
+name = {{ frontend_name }} for {{ theia_id }}
 
 {% if additional_frontend -%}
 [remote-additional-frontend]
-name = Import {{ parameter_dict['additional-frontend-name'] }}
+name = {{ parameter_dict['additional-frontend-name'] }} for {{ theia-id }}
 {%- endif %}