Develop -> Master

batch-submitter: Remove bad changeset, remove old build

feat: indexer service to replace etherscan dependency

Develop -> Master

cleanup(contracts): remove unused code

Develop -> Master

l2geth: Add support for system addresses

Adds support for system addresses.

To deploy to a system address, the deployer must either be in the list of hardcoded addresses described in `SystemAddressDeployers`, or be specified via the `SYSTEM_ADDRESS_0_DEPLOYER`/`SYSTEM_ADDRESS_1_DEPLOYER` environment variables. The hardcoded system addresses deployers will always override those placed in the environment, so specifying the `SYSTEM_ADDRESS_*` env vars on mainnet, Kovan, or Goerli is a no-op. The env vars are available primarily for testing purposes.

The contract deployment **must** be the first transaction from the deployment address - i.e., it must have nonce zero.

In order to make the tests work, I had to change the integration tests chain ID to no longer conflict with Goerli. The new integration tests chain ID is `987`.

Co-Authored-By: @inphi

Removes functions and constants that are not used in the contracts
package. Also removes export from interfaces that are not being imported.

fix(ct): remove yargs as unused dep

feat(sdk): add fn to wait for message status

feat: remove packages/batch-submitter

Removes yargs as a dependency from the contracts package since it wasn't
being used. Always good to cut unused dependencies.

Adds a function to the SDK (waitForMessageStatus) which will wait until
the status of a particular message matches the target status.
waitForMessageStatus also handles certain special cases where different
status messages are incompatible (e.g., the RELAYED and
FAILED_L1_TO_L2_MESSAGE status for L1 to L2 messages). Useful to avoid
including looping logic in your own application.

fix(bridge): Corrected a comment

fix(rhc): fix dockerfile bug

contracts: fetch batches hardhat task

increase coverage of contracts package

This commit increases the statement and branch coverage of the contracts
package. More specificall the contracts that were covered are:

- AddressDictator
- ChugSplashDictator
- L1CrossDomainMessenger
- L1StandardBridge
- CanonicalTransactionChain
- ChainStorageContainer
- StateCommitmentChain
- L2CrossDomainMessenger
- L2StandardBridge
- WETH9
- Lib_OVMCode
- Lib_RLPWriter
- Lib_SecureMerkleTrie
- Lib_Buffer
- Lib_MerkleTree

Allows for easy serialization and display in frontends
or for data collection

Adds a hardhat task to fetch batches. Logs are written
to stderr so that the stdout can be written to a file
or passed to `jq`.

```bash
export CONTRACTS_TARGET_NETWORK=...
export CONTRACTS_DEPLOYER_KEY=...
export CONTRACTS_RPC_URL=...
npx hardhat fetch-batches --network main --start 14311261
```

integration-tests: Fix merge issue

readme: update docs around doing releases

Remove unnecessary contract references in integration-tests

feat: always run go unit tests/golangci-lint on every PR

feat: typed batches and batch compression

added internal/external import seperation on integration tests

The current methodology only attempts to run unit tests when changes to
the package paths are detected. However, this is brittle and most
notably doesn't capture when changes are made to the workflow itself. As
a result, a green build in a PR doesn't neccessarily correlate to a
green build after merge. Unit tests are cheap, so this should prevent
needless false positives.

ci: Update nightly address manager addr, notify on itest failures