Refactoring + additional SQL functions

Scope of this MR covers also changes of !337 (merged) Please review them and leave only non redundant changes - I'd prefer 337 since it contains a lot of new tests added and eliminates redundant code of condenser_api calls (reuse bridge.get_ranked_post implementation).

added 68 commits

• 73b78f8c...51383624 - 64 commits from branch develop
• 067b48a0 - Removed temporary file included to repo by mistake
• 67935e72 - Not used methods are removed
• 6619ece6 - Introduced `condenser_get_discussions_by_comments` SQL function
• 4faeaf8d - Introduced `condenser_get_account_reputations` SQL function

Compare with previous version

All changes in this MR are unique and they aren't overlapped with changes from MR 337 at all

merged

mentioned in commit 16e88ceb