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

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.

Changed methodology for benchmarks

See merge request !352

Notification API performance optimizations

See merge request !353

Refactoring + additional SQL functions

See merge request !347

* Usage of pytest-benchmarks is dropped since it call tests
  sequentially which very long time to complete, instead original
  tavern tests are used
* Time measuring is done via durations switch to pytest and tavern
* During benchmarking validate_response.py is disabled using nevly
  introduced env variable
* Each run creates xml junit file with time data
* After all runs data from files are combined and report file is
  generated
* Tests above threshold are marked with red

Escape characters in user names provided in follow_op

See merge request !346

Run tests is now using tox environments

See merge request !350

* Reverted hardcoded block number and changed to use CI var HIVEMIND_MAX_BLOCK.
* Please add a possibility to set HIVEMIND_MAX_BLOCK.
* operation_extractor:
** name of parameter `hivemind_address` changed to `hived_url` as we
   scan blocks from `hived`
** added description to the script