New API: 'lock', 'unlock', 'lock_info'

[dmgav]

Implementation of the new API:

• lock - locks RE Manager (the worker environment and/or the queue) with user-provided lock key;
• unlock - unlocks RE Manager;
• lock_info - loads lock status and optionally validates the lock key.

The description of implemented functionality: https://blueskyproject.io/bluesky-queueserver/features_and_config.html#locking-re-manager

The detailed description of the API:

• https://blueskyproject.io/bluesky-queueserver/re_manager_api.html#lock
• https://blueskyproject.io/bluesky-queueserver/re_manager_api.html#lock-info
• https://blueskyproject.io/bluesky-queueserver/re_manager_api.html#unlock

Tutorial: https://blueskyproject.io/bluesky-queueserver/tutorial.html#locking-re-manager

Summary of Changes for Release Notes

Fixed

Added

• New lock, unlock and lock_info API. The API are accessible from CLI using qserver lock and qserver unlock commands.
• qserver-clear-lock CLI tool for unlocking RE Manager if the lock key is lost and the emergency lock key is not set or unknown.

Changed

Removed

How Has This Been Tested?

Comprehensive unit tests are implemented.