Support TLS in batcher connections

Description

Before this PR, the TLS connections where handled by a Caddy in the batcher servers.

Now with this PR, the TLS is handled directly in the batcher.

Notes for testing

As mentioned in the updated guide, you'll need to install mkcert. When running the make batcher_start_local command for the first time, it'll ask for authentication to install a locally generated root certificate. It's only needed for devnet.

You should be able to send and verify proofs normally after that.

Type of change

Please delete options that are not relevant.

• New feature
• Bug fix
• Optimization
• Refactor

Checklist

• “Hotfix” to testnet, everything else to staging
• Linked to Github Issue
• This change depends on code or research by an external entity
  • Acknowledgements were updated to give credit
• Unit tests added
• This change requires new documentation.
  • Documentation has been added/updated.
• This change is an Optimization
  • Benchmarks added/run
• Has a known issue
  • Link to the open issue addressing it
• If your PR changes the Operator compatibility (Ex: Upgrade prover versions)
  • This PR adds compatibility for operator for both versions and do not change batcher/docs/examples
  • This PR updates batcher and docs/examples to the newer version. This requires the operator are already updated to be compatible