Important: #100925 - Use dedicated cache for database schema information

See forge#100925


To implement native JSON database field and TCA type=json support for TYPO3 v12 the need to cache the database schema information raised due to performance reason.

Using the core cache for schema information comes with various drawbacks:

  1. There is no way to flush single core cache entries, thus the complete core cache needs to be flushed when changing the database schema.
  2. The PHP Frontend provides no benefit, when the to be cached information has to be serialized anyway.

Therefore, a new cache is introduced that can be flushed individually after schema updates.

Additionally, some internal steps taken to mitigate some side effects are reverted. They are no longer needed with the dedicated cache.

Due to the nature of the chosen cache no database updates, configuration changes or other steps are needed.