Introduced `condenser_get_names_by_reblogged` SQL method

Introduced `condenser_get_follow_counts` SQL method

Introduced `condenser_get_names_by_following` SQL method

Introduced `condenser_get_names_by_followers` SQL method

hive sync fixes

See merge request !342

Improved __post_children table management in the update_all_hive_posts_children_count, to avoid an error during subsequent call.

Added missed constrain rename.

See merge request !341

Bw db upgrade support2

See merge request !338

Defined separate update_all_hive_posts_children_count to significantly improve performance of massive calculation
Disabled seq scan during execution of update_posts_rshares call to improve performance
db_upgrade measures time of every executed statement
Runtime migration is performed in separated transaction instead of single one.

Fix for issue #65

See merge request !211

remove hive_follows_block_num_idx before sync

See merge request !335

Included commit of latest develop the upgrade procedure has been prepared for.

- reputation update is disabled during LIVE SYNC

Prepared upgrade scripts to process changes done in develop but not in deployed20200928_pure branch.

Mi follow validation crash

See merge request !334

db upgrade support

See merge request !333

database_api_vote, find_votes, list_votes_by_voter_comment, list_votes_by_comment_voter moved into database_api_list_votes.sql

find_account_id definition moved to utility_functions.sql
process_hive_post_operation definition moved to hive_post_operations.sql
delete_hive_post moved to hive_post_operations.sql

Original definition of process_hive_post_operation and delete_hive_post moved into hive_post_operations.sql

Moved original definition of find_comment_id and find_account_id functions from schema.py to utility_functions.sql file.

notification vote value fully processed in sql

See merge request !332

Mi drasticly speeds up notifications

See merge request !330

The bottleneck was score for  account computation. Only first
100,000 accounts with higest reputation got score different than
20, moreover only 2% of accounts have the same reputation value. Base on
this for score computation are taken only for first 150,000 of accounts (50,000 is a
safe buffor, just like 50% would have the same reputation)

There was a problem with local setting between python and sql,
vote value was returned with '.' or ',' from sql query depends
on locale setting. Python then process the value, but if it has
different locale setting than db it could not cast the value.
Now python does not process vote value generated by notification sql
query.