Feat/explorer settlement batch support

[stanlou]

Closes #147

This PR adds batch and settlement support to the explorer.

Changes

Indexer

• Added batch and settlement indexing and persistence in the database.
• Added GraphQL resolvers for batches and settlements.

Explorer UI

• Added batch list view.
• Added settlement list view.
• Refactored GraphQL queries to use variables instead of inline interpolation.
• Introduced reusable DataTable and shared filter components.

Landing Page

• Added a global search bar (blocks, transactions, settlements by hash).
• Displayed key network stats:
  • Total blocks
  • Total transactions
  • Current state root
  • Latest settlement
  • Latest block

[rpanic]

I have a few things that I noticed, but I think we should just add all of them as future tasks, i.e. future PRs. Just adding them here for completeness:

• Searching a block height shouldn't look for all the hashes that contain the block height, but instead I'd suggest searching for height only if the input is a number and less than the current max height (which we have access to, right?), and if the number is higher, we search for hashes

• Can we add the blocks view in the dashboard under the summaries? Kinda like https://etherscan.io/

• It would be cool if we could click on block hashes on the dashboard and get to the block's page right away

• For the transactions table inside the blocks view - can we use the same tick for the status that we use in the transaction detail page? Also, for failing transactions, lets display a x or something in red, while just adding the status message in the same column. I suspect most transactions to be successful, so the status message column would be mostly empty and it'd probably look better merged into one column.

• How hard is it to make the dashboard title and slogan configurable for users?

• Eventually, we should figure out if we want to display hashes as either hex or base64

• Also, we need to make a starter-kit PR to add the missing tasks to the module config

[rpanic]

Also, lets add a changelog to the Chanelog.md

[rpanic]

Also, lets add .next/ and next-env.d.ts to .gitignore as they are build artifacts