Abstract database specific helper methods to adapters

[bx80]

Description:

Fixes #19648

Moves all MySQL specific code from core/Db, core/DbHelper and all classes under core/Db/ to the database adapter classes core/Adapter/Pdo/Mysql, core/Adapter/Mysqli and a new shared class core/AdapterMysqlAdapterCommon` for methods common for both.

Updates for tracker Db classes core/Tracker/Db, core/Tracker/Db/Pdo/Mysql and core/Tracker/Db/Mysqli are also included.

The overall objective of these changes is to be able to add a new core/Db/Adapter/Pdo/[some new db], core/Db/Schema/[some new db] and core/Tracker/Db/Pdo/[[some new db] where 'some new db' supports prima facie MySQL style queries but has a different underlying architecture with differences in schema, indices, key type, engine type, error codes and session variables.

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

[bx80]

Closed in favor of #20112 due to 'not our ref' git error.