Do not auto discover i18n files.

Revert to the plain old 'i18n_resources_list.txt' file.

Auto discovering of i18n file has a main flaw (and a small bug):
- The main flaw is that rerun the configure will not detect new
  translation files. It means that if we use cache in our CI,
  new translation will not be included.
- The bug is that on Windows, meson fails with a error about a non existent
  `` (empty) file name. I suppose it is because python replace
  `\n` by `\r\n` on Windows, and the the `.strip().split('\n')` keeps empty
  lines.

The small bug could be fixed, but the main flaw make the whole better if
we use a script to generate the listing.

This commit is somehow a half revert of 2eff5b55a6

static/i18n_resources_list.txt

@@ -0,0 +1,2 @@
+i18n/en.json
+i18n/hy.json

static/meson.build

@@ -24,24 +24,17 @@ lib_resources = custom_target('resources',
     depends: preprocessed_resources
 )
 
-i18n_resource_listing_script = '''import glob
-import os
-import sys
-qqq = sys.argv[1]
-d = os.path.dirname(qqq)
-r = glob.glob(d + "/*.json")
-r.remove(qqq)
-for f in r: print(f)
-'''
-
-i18n_resource_listing_cmd = [
-                                find_program('python3'),
+# This could be replaced with
+# ```
+# fs = import('fs')
+# i18n_resource_files = fs.read('i18n_resources_list.txt').strip().split('\n')
+# ```
+# once we move to meson >= 0.57.0
+i18n_resource_files = run_command(find_program('python3'),
                                     '-c',
-                                i18n_resource_listing_script,
-                                files('i18n/qqq.json')
-                            ]
-
-i18n_resource_files = run_command(i18n_resource_listing_cmd).stdout().strip().split('\n')
+                                    'import sys; f=open(sys.argv[1]); print(f.read())',
+                                    files('i18n_resources_list.txt')
+                                 ).stdout().strip().split('\n')
 
 i18n_resources = custom_target('i18n_resources',
     input: i18n_resource_files,