MDL-34397 TEMP FIX FOR MDL-40830
MDL-34397 Reset cache in API functions instead of tests

- moveto_module() already resets the cache, no need to call reset in the tests
- groups_add_member() and groups_remove_member() must reset cache and tests must not
MDL-34397 Move course content cache to MUC
MDL-34397 small improvements to get_fast_modinfo()
MDL-34397 Removing references to course.modinfo
MDL-34397 Allow call rebuild_course_cache for multiple courses
MDL-34397 TODO
MDL-34397 Caching course format in modinfo

Also by passing the  object to sectioninfo constructor we save a query retrieving course format
MDL-34397 Object section_info calculates expensive data on demand only
MDL-34397 cm_info
MDL-34397 dont write to cm_info properties
MDL-34397 temp
MDL-34397 temp
MDL-34397 comments to cm_info
MDL-34397 more comments
MDL-34397 caching in cm_info (unpolished)
MDL-34397 unittest for usercache
MDL-34397 user section cache - unfinished