Overhaul core Tracker: add tests for databases mod

[josecelano]

Overhaul core Tracker: add tests for databases mod.

Regarding the database drivers these are the methods in the Database trait grouped by context:

Schema:

• create_database_tables
• drop_database_tables (this is only used for testing)

Persistent torrents (stats):

• load_persistent_torrents
• save_persistent_torrent

Authentication keys (for private trackers):

• load_keys
• get_key_from_keys
• add_key_to_keys
• remove_key_from_keys

Whitelist (for listed trackers):

• load_whitelist
• get_info_hash_from_whitelist
• add_info_hash_to_whitelist
• remove_info_hash_from_whitelist

Sub-tasks

• driver
  • mod.rs (no direct tests added)
  • mysql.rs
  • sqlite.rs
• error.rs
• mod.rs (no direct tests added)
• setup.rs (no direct tests added)

[codecov]

Codecov Report

Attention: Patch coverage is 70.35714% with 83 lines in your changes missing coverage. Please review.

Project coverage is 81.04%. Comparing base (24ae70d) to head (2cd1c65).
Report is 11 commits behind head on develop.

Files with missing lines	Patch %	Lines
...ackages/tracker-core/src/databases/driver/mysql.rs	11.76%	60 Missing and 15 partials ⚠️
packages/tracker-core/src/databases/error.rs	80.95%	0 Missing and 4 partials ⚠️
packages/tracker-core/src/databases/driver/mod.rs	97.72%	3 Missing ⚠️
...es/tracker-core/src/authentication/key/peer_key.rs	92.30%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1255      +/-   ##
===========================================
+ Coverage    80.96%   81.04%   +0.07%     
===========================================
  Files          206      206              
  Lines        14478    14748     +270     
  Branches     14478    14748     +270     
===========================================
+ Hits         11722    11952     +230     
- Misses        2581     2599      +18     
- Partials       175      197      +22     

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[josecelano]

I've found some bugs while writing tests. I will fix them in this PR because I'm almost done and It will be merge soon.

[josecelano]

ACK 2cd1c65