Nginx-amplify-agent-health-check

**Changelog**
- improve cli error handling
- modify cli options (`-k` and `--only` [for KEEP_METHODS] to `-m` and `--methods` [for METHODS])
- update tests

**Changelog:**
- add/update command line functionalities/options
- add ability to allow adding config options through ini format file via both cli and api interfaces
- bug fixes

**Changelog:**
- add ability to use directly via command line (i.e. by issuing `amphc`)
- improve error handling
- bug fixes
- update tests

**Changelog:**
- verify nginx parent process to ensure nginx is a foreground system process
- verify nginx stub_status config is included in nginx.conf
- add/modify tests

NGINX Amplify Agent Health Check

First Tested Release of NGINX Amplify Agent Health Check