- Adopts Go workspaces for future compatibility with the Bedrock move into the monorepo
- Moves Go packages to the root of the repo in order to fix import paths
- Rewrites existing Go import paths
- Removes Stackman, since it's not needed anymore
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

This commit adds the `gas-oracle` which is an offchain entity
that sends transactions to L2 to update the gas price. It must
be configured with a private key as the `OVM_GasPriceOracle`
is owned.

The `gas-oracle` is added to the changesets setup.

Tests are included as well as CI. Dockerizing will happen
in a follow up PR.

* pkg: import l2geth

* chore: add l2geth tests submodule

* ci: unit test l2geth

* chore: skip Android tests

* chore: cleanup ci