Add GQA and KV Cache

[dhernandez0]

This PR adds support for:

1. Tests for GQA and rocmlir-gen GQA implementation (--num_heads_q and --num_heads_kv)
2. KV Cache implementation: currentSeqLen to handle dynamic number of seqLen for K and V.

Note that MIGraphX integration will be done in a next ticket (we need to sync with them to decide how to do this). So, for now, TosaToRock sets currentSeqLen = nullptr.

[codecov]

Codecov Report

Attention: Patch coverage is 85.42199% with 57 lines in your changes missing coverage. Please review.

Project coverage is 78.25%. Comparing base (64ccaae) to head (f248ae5).
Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
mlir/tools/rocmlir-gen/rocmlir-gen.cpp	89.63%	18 Missing and 5 partials ⚠️
mlir/lib/Dialect/Rock/IR/RockDialect.cpp	27.58%	13 Missing and 8 partials ⚠️
...ialect/Rock/Transforms/GridwiseGemmToBlockwise.cpp	92.37%	7 Missing and 2 partials ⚠️
.../Dialect/Rock/Transforms/AffixTuningParameters.cpp	25.00%	3 Missing ⚠️
mlir/lib/Dialect/Rock/utility/builderUtils.cpp	92.85%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1696      +/-   ##
===========================================
+ Coverage    78.22%   78.25%   +0.02%     
===========================================
  Files          100      100              
  Lines        28009    28346     +337     
  Branches      4097     4130      +33     
===========================================
+ Hits         21910    22182     +272     
- Misses        4434     4484      +50     
- Partials      1665     1680      +15     

Flag	Coverage Δ
mfma	78.25% <85.42%> (+0.02%)	⬆️

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