Develop -> Master PR

maintenance: decrease geth diff

Remove some unused code

dtl: handle errors in context api

develop => master

Version Packages

develop => master

Both `GET /eth/context/latest` and `GET /eth/context/blocknumber/:number`
rely on fetching a remote block to pull the timestamp, blocknumber and
blockhash from. If the fetched block is not found, then properties on
`null` will be attempted to be accessed which will result in a runtime
error. This commit adds handling for this case to prevent that kind of
bug.

fix: correctly export SDK

master => develop

Version Packages

merge develop into master

fix(sdk): updated flaky test

fix: have sdk use ethers peer dep

build(deps): bump simple-get from 2.8.1 to 2.8.2

l2geth: update readme

maintenance: update ethers deps

feat: SDK beta release

Bumps [simple-get](https://github.com/feross/simple-get) from 2.8.1 to 2.8.2.
- [Release notes](https://github.com/feross/simple-get/releases)
- [Commits](https://github.com/feross/simple-get/compare/v2.8.1...v2.8.2)

---
updated-dependencies:
- dependency-name: simple-get
  dependency-type: indirect
...
Signed-off-by: dependabot[bot] <support@github.com>

feat(sdk): start using sdk in integration tests

feat(sdk): implement message wait time estimation

integration-tests: Remove superfluous nightly env tests

Fix Typo In Comment

These aren't needed anymore now that we've released the Berlin HF on Kovan and nightly has been reset.

feat(sdk): refactor into single messenger class

Extract core BSS logic into bss-core package