issue #91: incorrect results when initial sync started not from scratch

See merge request !354

fix incorrect volatile sql function type

See merge request !366

condenser get trending tags opt

See merge request !365

Changes in index definitions, to significantly speedup 'condenser_api.get_trending_tags' call. Dedicated index created: hive_posts_category_id_payout_plus_pending_payout_depth_idx
Other indexes (mostly used by bridge_api.get_ranked_posts) has been extended by WHERE condition to eliminate rows does not matching conditions. This way indexes size has been significantly reduced.

Recreate table deps_saved_ddl when doing db upgrade

See merge request !360

This reverts commit 4a9e1e14.

get account posts by feed fix

See merge request !362

branch 'bw_get_account_posts_by_feed_fix' of gitlab.syncad.com:hive/hivemind into bw_get_account_posts_by_feed_fix

Reimplemented condenser_api.get_discussions_by_feed to reuse bridge_api SQL function and match previous behavior

reusing code of bridge calls in condenser_api

See merge request !337

Merge branch 'bridge_code_reuse_in_condenser_api' of gitlab.syncad.com:hive/hivemind into bridge_code_reuse_in_condenser_api

Fix problem with collation,

Supplemented missing condition to get account posts by blog

See merge request !359

get account posts by blog fixes

See merge request !358

full sync tavern tests

See merge request !293

added missing .sql files to upgrade script

bridge_api.get_account_posts when sort = "feed" improvements

See merge request !357

Eliminated performance problems in the above implementation.
Defined 2 new indexes: hive_feed_cache_block_num_idx and hive_feed_cache_created_at_idx.

The problem was with column hive_stat.block_num which is used only as
a last synced block number, but it was set with a last block number
known by hived

Changed methodology for benchmarks

See merge request !352

Notification API performance optimizations

See merge request !353

Refactoring + additional SQL functions

See merge request !347