Improvements and bug fixes.

What's Changed

• Add user permissions by @VaghinakDev in #796
• fix in docs by @nareksa in #795
• added project category related functions by @nareksa in #798
• added item category set/remove functions by @nareksa in #799
• added contributor categories functions by @nareksa in #800
• fixed list_users by @nareksa in #801
• add categories arg validation by @nareksa in #802
• Fix categories by @nareksa in #803
• fix in set_remove_contributor_categories by @nareksa in #804
• version update by @nareksa in #805
• fix in UploadMultiModalAnnotationsUseCase by @nareksa in #807
• fix in tests by @nareksa in #808
• Remove ffmpeg from requirements by @VaghinakDev in #811
• Add form argument in create_project method by @VaghinakDev in #810
• updated changelog.rst by @nareksa in #812
• added include param in get_item_by_id by @nareksa in #814

Full Changelog: v4.4.36b1...v4.4.39dev1