dialects: (riscv) add rv32, rv64 dialects

[osmanyasar05]

This PR adds riscv32 and riscv64 dialects.

[codecov]

Codecov Report

❌ Patch coverage is 80.91286% with 46 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.21%. Comparing base (696f13f) to head (a0b4cd3).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
xdsl/transforms/canonicalization_patterns/rv64.py	57.14%	12 Missing and 3 partials ⚠️
xdsl/dialects/rv64.py	89.28%	7 Missing and 2 partials ⚠️
xdsl/transforms/canonicalization_patterns/rv32.py	82.85%	2 Missing and 4 partials ⚠️
xdsl/dialects/rv32.py	92.18%	3 Missing and 2 partials ⚠️
xdsl/interpreters/rv32.py	28.57%	5 Missing ⚠️
xdsl/interpreters/rv64.py	28.57%	5 Missing ⚠️
xdsl/transforms/canonicalization_patterns/riscv.py	88.88%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5589      +/-   ##
==========================================
- Coverage   86.25%   86.21%   -0.05%     
==========================================
  Files         403      405       +2     
  Lines       56660    56810     +150     
  Branches     6512     6531      +19     
==========================================
+ Hits        48871    48976     +105     
- Misses       6268     6303      +35     
- Partials     1521     1531      +10     

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[osmanyasar05]

@superlopuh I want to ask whether we are keeping some parts of the riscv dialect for shared constructs or is the aim to get rid of it altogether and copy everything in the rv32 and the rv64 dialects? also, I believe we need copies of the test files for both of the new dialects as well.

[superlopuh]

I'm not 100% sure, for now I would only touch the shift ops and think about the other ops later

[osmanyasar05]

Merged the changes. Should I move forward with moving more operations to the corresponding dialect files? @superlopuh

[osmanyasar05]

Added test cases in commits a531882, e0b50ea and 8adc7cb.

[osmanyasar05]

Merged changes from a259e76. Will work on getting shift instructions merged now.

[osmanyasar05]

Added comments to the operations and changed some wrong links to docs in comments.

[luisacicolini]

left a few style nits, otherwise lgtm - thank you!

[osmanyasar05]

left a few style nits, otherwise lgtm - thank you!

addressed these comments! now the PR only has changes related to shift instructions @superlopuh