feat: store skipped transactions in local db

[Thegaram]

1. Purpose or design rationale of this PR

This PR addresses the following problems:

• It is hard to detect which transactions were skipped.
• We need an easy way to check why a transaction was skipped. Now we log this information but the logs will be lost after a node is restarted.
• When we skip an L2 transaction, it's dropped completely. This makes it very hard to inspect this transaction.

To solve this, this PR adds the following:

• Store skipped transactions in the node's local db. We store 3 things: (1) For each skipped tx, we store hash => Transaction. (2) For each skipped transaction, we store skip index => TxHash (where skip index is a simple counter). (3) We store the count of skipped transactions.
• Expose 3 new APIs: scroll_getNumSkippedTransactions(), scroll_getSkippedTransaction(txHash), scroll_getSkippedTransactionHashes(fromIndex, toIndex). These are also conveniently exposed on the geth console.
• Populate the DB in worker for signer nodes, here we have detailed skip reasons. Populate the DB in block_validator for follower nodes, here we don't have the skip reason.

Caveats:

• If a node upgrades to this version, it will not re-index old skipped messages. For example, NumSkippedTransactions will be lower than the exact count.
• Signer and follower nodes will have different views. This includes different skip reasons. The information about which block skipped the message will also be different.

That said, these APIs are mainly for easier debugging, so these potential inconsistencies are acceptable.

2. PR title

Your PR title must follow conventional commits (as we are doing squash merge for each PR), so it must start with one of the following types:

• feat: A new feature

3. Deployment tag versioning

Has the version in params/version.go been updated?

• This PR doesn't involve a new deployment, git tag, docker image tag, and it doesn't affect traces
• Yes

4. Breaking change label

Does this PR have the breaking-change label?

• This PR is not a breaking change
• Yes

[icemelon]

lgtm. just one minor comment