[DOP-8511] Allow table name to have format db.schema.table

[dolfinus]

Kafka does not have restrictions for topic names, so some.topic.name is a valid string. But currently Table class (used in DBReader.source and DBWriter.target) does not allow such names.

This restriction was cause by validator which separated db.name to separated fields db and name. Replaced it with just one field name, bumped version to 1.4.0.

[codecov]

Codecov Report

Merging #21 (4c9b697) into develop (0d4bcb2) will decrease coverage by 0.07%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop      #21      +/-   ##
===========================================
- Coverage    96.99%   96.93%   -0.07%     
===========================================
  Files           32       32              
  Lines          599      587      -12     
  Branches       104      101       -3     
===========================================
- Hits           581      569      -12     
  Misses          10       10              
  Partials         8        8              

Files Changed	Coverage Δ
etl_entities/hwm/column_hwm.py	89.47% <ø> (ø)
etl_entities/hwm/date_hwm.py	100.00% <ø> (ø)
etl_entities/hwm/datetime_hwm.py	100.00% <ø> (ø)
etl_entities/hwm/int_hwm.py	100.00% <ø> (ø)
etl_entities/source/db/table.py	100.00% <100.00%> (ø)