Cassandra Schema and Value Mapping

[VardhanThigle]

Cassandra Schema and Data mapping for primitive types.

This PR covers mapping of primitive types to Avro for Cassansdra.
As of this PR, all the non-primitive types are mapped to null.

TODOS:

• spanner writer handling for the 2 new unified types introduced.
• end to end integration with pipeline options and CassandraIO.
• integration and lod testsing
• support for non-primitive types.

[codecov]

Codecov Report

Attention: Patch coverage is 99.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 53.80%. Comparing base (6a50180) to head (d5eac53).

Files with missing lines	Patch %	Lines
.../cassandra/mappings/CassandraMappingsProvider.java	97.95%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2048      +/-   ##
============================================
+ Coverage     45.98%   53.80%   +7.82%     
+ Complexity     3810     1456    -2354     
============================================
  Files           851      388     -463     
  Lines         50844    21093   -29751     
  Branches       5359     2114    -3245     
============================================
- Hits          23381    11350   -12031     
+ Misses        25760     9062   -16698     
+ Partials       1703      681    -1022     

Components	Coverage Δ
spanner-templates	69.07% <99.33%> (+1.47%)	⬆️
spanner-import-export	∅ <ø> (∅)
spanner-live-forward-migration	76.42% <100.00%> (+0.11%)	⬆️
spanner-live-reverse-replication	77.35% <100.00%> (+0.09%)	⬆️
spanner-bulk-migration	87.17% <99.33%> (+0.29%)	⬆️

Files with missing lines	Coverage Δ
...eader/io/cassandra/mappings/CassandraMappings.java	100.00% <100.00%> (ø)
.../cassandra/rowmapper/CassandraSourceRowMapper.java	100.00% <100.00%> (ø)
...rce/reader/io/cassandra/rowmapper/FieldMapper.java	100.00% <100.00%> (ø)
...ource/reader/io/cassandra/rowmapper/RowMapper.java	100.00% <100.00%> (ø)
.../io/cassandra/schema/CassandraSchemaDiscovery.java	98.24% <ø> (ø)
...eader/io/schema/typemapping/UnifiedTypeMapper.java	100.00% <100.00%> (ø)
...ema/typemapping/provider/unified/CustomSchema.java	100.00% <100.00%> (ø)
...pping/provider/unified/UnifiedMappingProvider.java	100.00% <100.00%> (ø)
...er/migrations/avro/GenericRecordTypeConvertor.java	93.58% <100.00%> (+0.46%)	⬆️
.../cassandra/mappings/CassandraMappingsProvider.java	97.95% <97.95%> (ø)

... and 485 files with indirect coverage changes