Refactor Settings DB and Handling

[Lord-Grey]

Summary

Allow more fine grained get and update config API calls.
The configuration database is now validated before starting Hyperion, as well as migrated if required.

Breaking

• Global global configuration elements are now separated form instance specific ones

Added

• Support to import, export and backup Hyperion's full configuration via the UI, JSON-API and commandline (--importConfig, --exportConfig) (Configuration export/import for multiple instances #804)
• Allow to force starting Hyperion in read-only mode (--readonlyMode)
• JSON-API: Support to query for a dedicated set of configuration items for a set of instances
• JSON-API: Support to save a dedicated set of configuration items for a set of instances

Changed

• Refactored Database access layer
• Refactored: Hyperion's configuration database is validated before start-up (and migrated, if required)

JSON-API

• Fixed: Local Admin API Authentication rejects valid tokens (Local Admin API Authentication rejects valid tokens #1251)

What kind of change does this PR introduce? (check at least on

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
• Other, please describe:

If changing the UI of web configuration, please provide the before/after screenshot:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing setups:

The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's body (e.g. Fixes: #xxx[,#xxx], where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature
• Related documents have been updated (docs/docs/en)
• Related tests have been updated

PLEASE DON'T FORGET TO ADD YOUR CHANGES TO CHANGELOG.MD

• Yes, CHANGELOG.md is also updated

To avoid wasting your time, it's best to open a feature request issue first and wait for approval before working on it.

Other information:
fixes #804
fixes #1251