Introduce new messaging mechanism

The logging mechanism of gpupdate is in poor state at the moment.
This commit introduces Oracle-style messages with codes. The messages
are not format strings and may be easily localized and it is also
easy to refer to specific problem.

The original idea is to permanently assign error codes only expanding
code lists during time in order to deliver reliable product.

gpoa/messages/__init__.py

@@ -0,0 +1,65 @@
+#
+# GPOA - GPO Applier for Linux
+#
+# Copyright (C) 2019-2020 BaseALT Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+def info_code(code):
+    info_ids = dict()
+    info_ids[1] = ''
+    info_ids[2] = ''
+
+    return info_ids.get(code, 'Unknown info code')
+
+def error_code(code):
+    error_ids = dict()
+    error_ids[1] = 'Insufficient permissions to run gpupdate'
+    error_ids[2] = 'gpupdate will not be started'
+
+    return error_ids.get(code, 'Unknown error code')
+
+def debug_code(code):
+    debug_ids = dict()
+    debug_ids[1] = ''
+    debug_ids[2] = ''
+
+    return debug_ids.get(code, 'Unknown debug code')
+
+def warning_code(code):
+    warning_ids = dict()
+    warning_ids[1] = ''
+    warning_ids[2] = ''
+
+    return warning_ids.get(code, 'Unknown warning code')
+
+def get_message(code):
+    retstr = 'Unknown message type, no message assigned'
+
+    if code.startswith('E'):
+        retstr = error_code(int(code[1:]))
+    if code.startswith('I'):
+        retstr = info_code(int(code[1:]))
+    if code.startswith('D'):
+        retstr = debug_code(int(code[1:]))
+    if code.startswith('W'):
+        retstr = warning_code(int(code[1:]))
+
+    return retstr
+
+def message_with_code(code):
+    retstr = '[' + code[0:1] + code[1:].rjust(5, '0') + ']: ' + get_message(code)
+
+    return retstr
+