maintenance: minor README updates

Version Packages

Develop -> Master

fix: skip an unreliable integration test

Skips the unreliable timestamp/blocknumber test which would often be off
by one or two. Creates an annoying habit of having to rerun the
integration tests until the test passes, which isn't how integration
tests should work.

go/proxyd: Handle nil responses better

fix: use correct token for label-requires-review

This check is the only one we have that uses PERSONAL_ACCESS_TOKEN,
perhaps it's expired or not present.

fix: make relayer work again

fix: remove extra space in BSS metric names

Fixes a bug where the relayer package was not correctly running the
start script since the start script updated recently.

feat: unify BSS metric name format, switch num_elements_per_batch to Summary

bss: properly set gas limit on clearing txs

feat: add LOG_TERMINAL flag, default to JSON

test(integration): replace watcher with sdk CrossChainMessenger

The histogram doesn't seem to render too well on Grafana, but the
batch_size_bytes one does. This commit modifies the
num_elements_per_batch to also use a Summary with the same buckets.

This commit:
 - Ensures each bss metric is prefixed by "batch_submitter_".
 - Ensures that Sequencer/Proposer name is made lowercase.
 - Ensures all units are present and positioned as a suffix.

This commit modifies the BSS to default to JSON logs, which are more
useful in production. This can be overridden by setting
LOG_TERMINAL to true for debugging locally.

feat(sdk): have SDK sort messages descending by bn

Fixes a bug where clearing txs are rejected on startup if the gas limit
is not set.

This was overlooked when
https://github.com/ethereum-optimism/optimism/pull/2107 was merged.

Has the SDK sort messages (deposits/withdrawals) descending by block
number. Makes for a better experience when presenting this data to
users.

feat(sdk): remove getTokenBridgeMessages function

Removes the getTokenBridgeMessagesByAddress function from the SDK. This
function is not particularly useful and its behavior is confusing. It's
much easier for users of the package to simply use getDepositsByAddress
and getWithdrawalsByAddress separately, since this is already what
getTokenBridgeMessagesByAddress was doing under the hood.

refactor: improve core-utils folder structure

Improves the folder structure within the core-utils to make it more
intuitive. core-utils is now split into three primary folders, "common",
"external", and "optimism". "common" includes TypeScript/JavaScript
utilities not necessarily meant to be used with any particular package
(like hex string utilities). "external" includes utilities that are
meant to be used in conjunction with some other particular piece of
tooling (ethers provider utilities, geth typings). "optimism" includes
any utilities that are specifically meant to be used in the context of
Optimism (like address aliasing utils, batch encoding utils).

test: misc.ts in core-utils

maintenance: remove regenesis-surgery package

Removes the regenesis-surgery package. The contents of this package are
not being actively used in any capacity. We can look at Git history if
we ever want to access the code again, but it's unlikely that we'll need
this code because we've committed to not doing another regenesis.

feat(sdk): implement asL2Provider

Replaces usage of injectL2Context with the new asL2Provider function
which is intended to eventually replace injectL2Context entirely.