Use grpc on the testing localnet

[xmariachi]

Purpose of Changes and their Description

• Add grpc support on test localnet.
• Add TLS support with self-signed cert.
• Ability to use TLS_PROXY and CERT_DIR env vars on the localnet script.

Link(s) to Ticket(s) or Issue(s) resolved by this PR

Are these changes tested and documented?

• If tested, please describe how. If not, why tests are not needed.
• If documented, please describe where. If not, describe why docs are not needed. -- Added to README
• Added to Unreleased section of CHANGELOG.md?

[amimart]

Oh nice thx