[DRAFT] Add Flextesa as a CI/CD integration test target + docs

[jevonearth]

Improved docs, but not complete.
Made changes to config.ts. Related work in ecadlabs/tezos-key-gen-api#31 is depended on by this PR

Todo:

• If user re-runs /flextesa-setup/deploy-flextesa-contracts.ts it does not update /integration-tests/config.ts. Impracticle if switching a sandbox between protocols.
• The When starting flextesa, block 0 and 1 will have specific protocols to get the chain running. The flextesa setup script discovers the protocol from the current head, but if the script is run before block level 3, it will get one of the bootstrap protocols. Example for flobox
  • 0 - PrihK96nBAFSxVL1GLJTVhu9YnzkMFiBeuJRPA8NwuZVZCE1L6i
  • 1 - Ps9mPmXaRzmzk35gbAYNCAw6UXdE2qoABTHbN2oEEc1qM7CwT9P
  • 2 - PsFLorenaUUuikDWvMDr6fGBRG8kt3e3D3fHoXK1j1BFRxeSH4i