Adds documentation for the VMs bytecode

[Lichtso]

Put together from various pieces that @riptl @CantelopePeel and myself worked on 8 months ago: https://github.com/firedancer-io/specs-old/blob/main/docs/protocol/sealevel/sbf/isa.md https://github.com/firedancer-io/solana-improvement-documents/blob/sbpf-v2-spec/proposals/9999-sbpf-v2.md

Additionally wrote about the verifier and ISA version differences.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.43%. Comparing base (c478374) to head (7a6e742). Report is 4 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #579 +/- ## ========================================== + Coverage 89.41% 89.43% +0.01% ========================================== Files 23 23 Lines 9998 9993 -5 ========================================== - Hits 8940 8937 -3 + Misses 1058 1056 -2 ```

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