## Proposed Changes
Lots of lint updates related to `flat_map`, `unwrap_or_else` and string patterns. I did a little more creative refactoring in the op pool, but otherwise followed Clippy's suggestions.
## Additional Info
We need this PR to unblock CI.
## Proposed Changes
Somehow since Lighthouse v1.1.3 the behaviour of `git-describe` has changed so that it includes the version tag, the number of commits since that tag, _and_ the commit. According to the docs this is how it should always have behaved?? Weird!
https://git-scm.com/docs/git-describe/2.30.1
Anyway, this lead to `lighthouse_version` producing this monstrosity of a version string when building #2194:
```
Lighthouse/v1.1.3-v1.1.3-5-gac07
```
Observe it in the wild here: https://pyrmont.beaconcha.in/block/694880
Adding `--exclude="*"` prevents `git-describe` from trying to include the tag, and on that troublesome commit from #2194 it now produces the correct version string.
## Issue Addressed
NA
## Proposed Changes
- Moves the git-based versioning we were doing into the `lighthouse_version` crate in `common`.
- Removes the `beacon_node/version` crate, replacing it with `lighthouse_version`.
- Bumps the version to `v0.2.0`.
## Additional Info
There are now two types of version string:
1. `const VERSION: &str = Lighthouse/v0.2.0-1419501f2+`
1. `version_with_platform() = Lighthouse/v0.2.0-1419501f2+/x86_64-linux`
(1) is handy cause it's a `const` and shorter. (2) has platform info so it's more useful. Note that the plus-sign (`+`) indicates the the git commit is dirty (it used to be `(modified)` but I had to shorten it to fit into graffiti).
These version strings are now included on:
- `lighthouse --version`
- `lcli --version`
- `curl localhost:5052/node/version`
- p2p messages when we communicate our version
You can update the version by changing this constant (version is not related to a `Cargo.toml`):
b9ad7102d5/common/lighthouse_version/src/lib.rs (L4-L15)
