Add missing docs to rollup-interface. Cleanup module structure.

[preston-evans98]

Description

• Add missing docs to rollup-interface
• Cleanup unneeded code instead of documenting it
  • Remove MerkleHasher trait
  • Remove CanonicalHash trait and instead add a hash method to BlockHeaderTrait
  • Remove the standalone traits module, and move its contents into either state_machine/mod.rs or the state_machine/da.rs files as appropriate.
  • Remove unnecessary nesting of modules; everywhere that there was a top-level module with no direct contents and exactly one child module, bring replace the parent with the child.

N.B. This PR makes no functional changes - only minor refactoring and docs improvements

Linked Issues

• Related to Cleanup: Add missing docs/tests to existing code #438

[codecov]

Codecov Report

Merging #483 (31bf396) into main (e542d7e) will increase coverage by 0.0%.
The diff coverage is 9.0%.

Impacted Files	Coverage Δ
adapters/celestia/src/celestia.rs	61.4% <0.0%> (ø)
adapters/celestia/src/verifier/address.rs	74.3% <ø> (ø)
adapters/celestia/src/verifier/mod.rs	0.0% <ø> (ø)
adapters/risc0/src/guest.rs	0.0% <ø> (ø)
adapters/risc0/src/host.rs	0.0% <ø> (ø)
adapters/risc0/src/lib.rs	9.0% <ø> (ø)
...-implementations/sov-prover-incentives/src/call.rs	90.2% <ø> (ø)
...plementations/sov-prover-incentives/src/genesis.rs	95.2% <ø> (ø)
...e-implementations/sov-prover-incentives/src/lib.rs	54.2% <ø> (ø)
...implementations/sov-prover-incentives/src/query.rs	92.3% <ø> (ø)
... and 14 more