[TASK] Deprecate usages of CharsetConverter in core

CharsetConverter is still instantiated in some places and not needed at all times.

The following places have CharsetConverter completely removed (as internal property):
- PageRenderer
- SearchController
- Indexer

The AbstractHierarchicalFilesystemDriver's shorthand method getCharsetConversion()
has been deprecated, as drivers should instantiate the CharsetConversion themself.

Indexed Search's Lexer has a public property "csObj" which has been switched to
protected, where a deprecation message will be thrown.

Resolves: #85125
Releases: master
Change-Id: I48fd110ecd25bb6a4225a3d2141edc5fc3b92673
Reviewed-on: https://review.typo3.org/57097


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>