feature: support systemd sd_notify protocol

[Bodong-Yang]

Introduction

This PR adds support for system sd_notify protocol, supporting otaclient-logger service running with Type=notify.

Motivation

By default, systemd service is labelled as active running as soon as the main process forked off.
Our new otaclient-logger is feature-rich than the original old one from otaclient, however
it comes with a drawback which it takes slightly more time to start up.
It results in an edge condition that, even we set the startup order to let otaclient-logger starts before otaclient, otaclient might still start faster than otaclient-logger service itself is ready(there is a small time gap between the service is forked off and the service is ready), resulting in some of the logs being dropped.

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
src/otaclient_iot_logging_server
__init__.py	3	0	100%
__main__.py	18	1	94%	49
_common.py	15	0	100%
_log_setting.py	27	10	62%	63, 65–66, 68–69, 73–74, 77–78, 80
_sd_notify.py	33	8	75%	42, 52, 57–59, 65–67
_utils.py	53	2	96%	73, 137
_version.py	8	0	100%
aws_iot_logger.py	100	55	45%	65–67, 69–72, 75, 81–87, 90–92, 95–100, 104–107, 111–113, 116–118, 121–126, 139, 145–147, 149–153, 157, 197, 204–207
boto3_session.py	35	9	74%	50, 58–59, 61, 78–79, 83, 85, 93
config_file_monitor.py	43	6	86%	64–66, 83–85
configs.py	44	1	97%	74
ecu_info.py	37	1	97%	75
greengrass_config.py	96	5	94%	155, 266–269
log_proxy_server.py	44	12	72%	52, 77–79, 88–90, 92, 94–95, 100, 106
TOTAL	556	110	80%

Tests	Skipped	Failures	Errors	Time
44	0 💤	0 ❌	0 🔥	11.874s ⏱️

[sonarqubecloud]

Quality Gate failed

Failed conditions
65.3% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud