In MultiRU there will be only one ENB which supports all TDD, FDD, LTE and NR
cells and different types of radio units - all at the same time. This patch is
preparatory step for that: it merges gnb configuration template into enb
configuration template, so that enb.jinja2.cfg now serves both enb and gnb
instances.

In this patch for now we only move code from gnb.jinja2.cfg without changing
it(*) and wrap parts with `if do_lte` and `if do_nr` correspondingly.

The end result of rendered enb.cfg and gnb.cfg stays the same modulo space
changes and added innoccent `#define TDD` as Appendix shows.

(*) the only exception is set up of gtp_addr which has practically the same
code, was wrapped with `if mme_list` in enb and `if amf_list` in gnb, and is now
wrapped with `if mme_list or amf_list`.

/cc @lu.xu, @tomo, @xavier_thompson, @Daetalus
/reviewed-by @jhuge
/reviewed-on !1512

--------

Appendix. Diff for rendered enb.cfg and gnb.cfg before and after this patch.

```
$ ./pythonwitheggs slapos-render-config.py && (git diff -w --no-index config/enb.cfg.old config/enb.cfg ; git diff -w --no-index config/gnb.cfg.old config/gnb.cfg)
```

```diff
diff --git a/config/enb.cfg.old b/config/enb.cfg
index fdf3ab24d..cb46697ea 100644
--- a/config/enb.cfg.old
+++ b/config/enb.cfg
@@ -1,11 +1,15 @@

+
 #define TDD                 1

 #define N_RB_DL             50
+
 #define N_ANTENNA_DL        2
+
 #define N_ANTENNA_UL        2

+
 {

   log_options: "all.level=error,all.max_size=0,nas.level=debug,nas.max_size=1,s1ap.level=debug,s1ap.max_size=1,x2ap.level=debug,x2ap.max_size=1,rrc.level=debug,rrc.max_size=1,phy.level=info,file.rota>
@@ -24,7 +28,6 @@
   rx_gain: 43,

   com_addr: "127.0.1.2:9001",
-
   mme_list: [

     {
@@ -33,9 +36,9 @@

   ],

+
   gtp_addr: "127.0.1.1",

-
   enb_id: 0x1A2D0,

   cell_list: [{
@@ -49,7 +52,6 @@
       ],
     }
   ],
-
   cell_default: {
     plmn_list: [
       "00101",
@@ -226,4 +228,6 @@
   meas_gap_config: "gp0",
   ho_from_meas: true,
   },
+
+
 }
\ No newline at end of file
diff --git a/config/gnb.cfg.old b/config/gnb.cfg
index e3d671e09..4e47a2094 100644
--- a/config/gnb.cfg.old
+++ b/config/gnb.cfg
@@ -1,15 +1,21 @@

+
+#define TDD                 1
+
+
 #define N_ANTENNA_DL        2

 #define N_ANTENNA_UL        2

+
 {

   log_options: "all.level=error,all.max_size=0,nas.level=debug,nas.max_size=1,ngap.level=debug,ngap.max_size=1,xnap.level=debug,xnap.max_size=1,rrc.level=debug,rrc.max_size=1,phy.level=info,file.rota>

   log_filename: "log/gnb.log",

+
   rf_driver: {
       name: "sdr",
       args: "dev0=/dev/sdr0",
@@ -30,15 +36,17 @@
   ],

-
-
   gtp_addr: "127.0.1.1",

   gnb_id_bits: 28,
   gnb_id: 0x12345,
   en_dc_support: true,
-  cell_list: [],
+
+  cell_list: [
+  ],
+
+
   nr_cell_list: [
   {
     rf_port: 0,
```