Add equals() and hashCode() methods to topic description classes

[Eistern]

This PR introduces proper equals() and hashCode() implementations to classes used during topic description operations. These implementations follow standard Java equality contract patterns and allow for reliable comparison of description objects.

[Eistern]

Dependent on the #476

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 19.90741% with 173 lines in your changes missing coverage. Please review.

Project coverage is 58.28%. Comparing base (943d5aa) to head (6f3d0f5).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
...main/java/tech/ydb/topic/impl/TopicClientImpl.java	23.63%	41 Missing and 1 partial ⚠️
...gs/AlterAutoPartitioningWriteStrategySettings.java	0.00%	20 Missing ⚠️
...a/tech/ydb/topic/description/TopicDescription.java	0.00%	15 Missing ⚠️
...h/ydb/topic/description/ConsumerPartitionInfo.java	0.00%	12 Missing ⚠️
...ava/tech/ydb/topic/description/PartitionStats.java	0.00%	11 Missing ⚠️
...main/java/tech/ydb/topic/description/Consumer.java	0.00%	10 Missing ⚠️
.../ydb/topic/settings/AlterPartitioningSettings.java	0.00%	10 Missing ⚠️
...ettings/AutoPartitioningWriteStrategySettings.java	65.38%	9 Missing ⚠️
...java/tech/ydb/topic/description/PartitionInfo.java	0.00%	8 Missing ⚠️
...in/java/tech/ydb/topic/description/TopicStats.java	0.00%	8 Missing ⚠️
... and 5 more

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #480      +/-   ##
============================================
- Coverage     58.76%   58.28%   -0.48%     
- Complexity     2170     2178       +8     
============================================
  Files           320      323       +3     
  Lines         12942    13159     +217     
  Branches       1269     1318      +49     
============================================
+ Hits           7605     7670      +65     
- Misses         4720     4866     +146     
- Partials        617      623       +6     

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