[2.0.0-alpha3] Move Field-related sources from ui_pattern_field_formatters to ui_patterns

to review

Finally : lot of classes renamed, some removed, cleaner code, better code.
some mechanisms removed, like the "getDiscoveryContexts" which is not really required anymore thanks to a few context_definitions annotations and the use of the new mechanism "RequirementsContext".
many thanks for Christian with his super remarks in DM.

100 lines of codes removed :)

the implementation has been prepared also for the merge of issue 3414293 📌 [2.0.0-alpha3] Implement PropTypeInterface::convertFrom() Needs review .

please let's review and merge if everything is ok, a much needed refactoring and cleaning.

Merged! and Cool!