Bloc updates

Solves the update of Bloc and associated libraries to v.4.x.x and the corresponding persistence changes in Hydrated_Bloc to Hive

Tests done:

• User (inkl. Badges) @pgrg81
• Timeline @clep09
• vCard @mblt41
• Home @jsar97
• cafeteria @dbrb56
• organizer @mlbn33

Known Issues:

• cafeteria: selected cafeterias are not persisted (even on Master sometimes settings get lost, i don't know why, seems like a localized problem.)
• general: migration of pre-Hive data does not work. (It does work as long as your persistence is sound in general.)
• organizer: selected courses lose color. (even happens on master, also seems like a localized problem)
• organizer: after migration: tried to call [] on null (could not reproduce yet... M.L. @jsar97 found it :) it will be fixed by the new error handling branch)
• timeline: _InternalLinkedHashMap errors
• user: does not persist showcased badges (as stated in #100 (closed) it's a known issue)

Just Now: Bloc-library updates to 5.0.0 ... => This should get an own MR. Issue open in: #148 (closed)

closes #128 (closed)