Feat CCT-966: Include timezone in the logs

In `subscription-manager/src/rhsm/logutil.py`i:

* New loggin formater class `RhsmISO8601Formatter` was made
to ensure that time stamp entry is in ISO-8810 format and
that it contains info about milliseconds and time zone.

CARD CCT-965

note.txt

@@ -0,0 +1,5 @@
+Today:
+  - detailed iteration of my mailbox -> finished some forgotten undone "formal" tasks (e.g. CITI card activation)
+  - CCT-965: finding out solution for impossibility to simply have microseconds rounded to millisecons and simultaneously time zone in log timestamp
+  - CSI retro & prioritization meetings
+

src/rhsm/logutil.py

@@ -10,13 +10,15 @@
 
 from typing import Optional, Tuple, Union, List
 
+import datetime
 import logging
 import logging.handlers
 import logging.config
 import os
 import sys
 import rhsm.config
 
+
 LOGFILE_DIR = "/var/log/rhsm/"
 LOGFILE_PATH = os.path.join(LOGFILE_DIR, "rhsm.log")
 USER_LOGFILE_DIR = os.path.join(
@@ -145,22 +147,32 @@ def __init__(self, name) -> None:
         self.addFilter(PyWarningsLoggingFilter(name="py.warnings"))
 
 
+class RhsmISO8601Formatter(logging.Formatter):
+    """Ensure date & time to be in ISO8601 format and containing info about milliseconds and time zone"""
+
+    def __init__(self):
+        super().__init__(fmt=LOG_FORMAT)
+
+    def formatTime(self, record, datefmt=None):
+        return datetime.datetime.fromtimestamp(record.created).astimezone().isoformat(timespec="milliseconds")
+
+
 def _get_default_rhsm_log_handler() -> (
     Tuple[Union[logging.handlers.RotatingFileHandler, logging.StreamHandler], Optional[str]]
 ):
     global _rhsm_log_handler
     error: Optional[Exception] = None
     if not _rhsm_log_handler:
         _rhsm_log_handler, error = RHSMLogHandler(LOGFILE_PATH, USER_LOGFILE_PATH)
-        _rhsm_log_handler.setFormatter(logging.Formatter(LOG_FORMAT))
+        _rhsm_log_handler.setFormatter(RhsmISO8601Formatter())
     return _rhsm_log_handler, error
 
 
 def _get_default_subman_debug_handler() -> Union[None, "SubmanDebugHandler"]:
     global _subman_debug_handler
     if not _subman_debug_handler:
         _subman_debug_handler = SubmanDebugHandler()
-        _subman_debug_handler.setFormatter(logging.Formatter(LOG_FORMAT))
+        _subman_debug_handler.setFormatter(RhsmISO8601Formatter())
     return _subman_debug_handler