[community pipeline] Add RF-inversion Flux pipeline (huggingface#9816)

* initial commit

* update denoising loop

* fix scheduling

* style

* fix import

* fixes

* fixes

* style

* fixes

* change invert

* change denoising & check inputs

* shape & timesteps fixes

* timesteps fixes

* style

* remove redundancies

* small changes

* update documentation a bit

* update documentation a bit

* update documentation a bit

* style

* change strength param, remove redundancies

* style

* forward ode loop change

* add inversion progress bar

* fix image_seq_len

* revert to strength but == 1 by default.

* style

* add "copied from..." comments

* credit authors

* make style

* return inversion outputs without self-assigning

* adjust denoising loop to generate regular images if inverted latents are not provided

* adjust denoising loop to generate regular images if inverted latents are not provided

* fix import

* comment

* remove redundant line

* modify comment on ti

* Update examples/community/pipeline_flux_rf_inversion.py

Co-authored-by: hlky <hlky@hlky.ac>

* Update examples/community/pipeline_flux_rf_inversion.py

Co-authored-by: hlky <hlky@hlky.ac>

* Update examples/community/pipeline_flux_rf_inversion.py

Co-authored-by: hlky <hlky@hlky.ac>

* Update examples/community/pipeline_flux_rf_inversion.py

Co-authored-by: hlky <hlky@hlky.ac>

* Update examples/community/pipeline_flux_rf_inversion.py

Co-authored-by: hlky <hlky@hlky.ac>

* Update examples/community/pipeline_flux_rf_inversion.py

Co-authored-by: hlky <hlky@hlky.ac>

* Update examples/community/pipeline_flux_rf_inversion.py

Co-authored-by: hlky <hlky@hlky.ac>

* fix syntax error

---------

Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
Co-authored-by: hlky <hlky@hlky.ac>