Implement writing down to db for LvmtStore

[rongma7]

This PR implements writing to the database for LvmtStore within the commit function.

• For amt_node_store, key_value_store, and slot_alloc_store, the corresponding updates are written to their pending parts. Writing to the history part is beyond the scope of LvmtStore.
• The auth_changes is a KeyValueStoreBulks, which typically only supports appending. Therefore, all commits, even if they are removed but not confirmed, are written to auth_changes, so consider gc_commit elsewhere. To enable committing auth_changes, the Key type of AuthChangeTable should be changed to ChangeKey to allow the auth_changes to satisfy the KeyValueStoreBulksTrait.

Additionally, references to CommitID have been updated to use the type alias, retaining H256 for other purposes.

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This change is 

[ChenxingLi]

Reviewed 2 of 3 files at r1, all commit messages.
Reviewable status: 2 of 3 files reviewed, 1 unresolved discussion (waiting on @rongma7)

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src/lvmt/storage.rs line 100 at r1 (raw file):

        // - Write to the history part is beyond the range of [`LvmtStore`].
        // - The `auth_changes` in [`LvmtStore`] includes all commits, even if they are removed but not confirmed,
        //   so consider `gc_commit` elsewhere.

Use TODO: comments for future work.

Avoid using markdown-style comments inside function.

[rongma7]

Reviewable status: 2 of 3 files reviewed, 1 unresolved discussion (waiting on @ChenxingLi)

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src/lvmt/storage.rs line 100 at r1 (raw file):

Previously, ChenxingLi (Chenxing Li) wrote…

Use TODO: comments for future work.

Avoid using markdown-style comments inside function.

Done.

[ChenxingLi]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @rongma7)