Add GLIGEN implementation (#4441)
* Add GLIGEN implementation
* GLIGEN: Fix code quality check failures
* GLIGEN: Fix Import block un-sorted or un-formatted failures
* GLIGEN: Fix check_repository_consistency failures
* GLIGEN: Add 'PositionNet' to versatile_diffusion/modeling_text_unet.py
* GLIGEN: check_repository_consistency: fix 'copy does not match' error
* GLIGEN: Fix review comments (1)
* GLIGEN: Fix E721 Do not compare types, use `isinstance()` failures
* GLIGEN : Ensure _encode_prompt() copy matches to StableDiffusionPipeline
* GLIGEN: Fix ruff E721 failure in unidiffuser/test_unidiffuser.py
* GLIGEN: doc_builder: restyle pipeline_stable_diffusion_gligen.py
* GIGLEN: reset files unrelated to gligen
* GLIGEN: Fix documentation comments (1)
* GLIGEN: Fix review comments (2)
* GLIGEN: Added FastTest
* GLIGEN: Fix review comments (3)
