[BUGFIX] Replace all t3lib_ occurrences

Replace all t3lib_ occurrences with namespaced
successors. t3lib will be completely removed
in 6.2.

Change-Id: Idf6ac09b32daa5fe0c6a2e3ca3651318de6832fd
Releases: 0.2.0
Fixes: #51045
[FEATURE] Introduce inline editing of FE groups

Change-Id: I8fb27e073781f794bd9cf2f4ec8a2f389bf98d28
Releases: 0.2.0
Fixes: #51296
[TASK] Clean up JavaScript

Change-Id: Idd96a976a828ce145b299f470443d40416384f44
[CLEANUP] Code clean up

Change-Id: I2c334dba3633f69b55c72301b84452f7c5ed0aea
[TASK] Improve CSS for form

Change-Id: I23893f78e44388b8d4864ede6317955ca5ec73f9
[TASK] Add class on DOM element

Change-Id: I7a934d2b2743df688f06f0afb6455e40a6b23973
[FEATURE] Add query support for one to many

Change-Id: I788bc21b4b1f1805b8bccdbaf75fe153efdbe967
Releases: 0.2.0
Fixes: #51306
[FEATURE] Improve support of datetime fields

Follow-up: #50822
Releases: 0.2.0
Change-Id: I2cdbf6e5c834455e343f2d83cfe62740f7c44e92