feat: Apply Google style recommendations

[bpcreech]

This is a speculative PR just to show losalex@, will add issue if it seems like a good idea.

Fixes #TODO

Things our formatter does to this codebase:

1. Add { } consistently after if statements. No one-liners-without-curlies allowed.
2. Group overloaded methods together
3. lowerCamelCase variables (e_name -> eName)
4. UPPER_SNAKE_CASE enums ~Label.ClusterName -> Label.CLUSTER_NAME). This would be a breaking change if the enum were intended to be public. I think Label's not supposed to be (altho it is protected so it could be...). I had to change the clirr allowlist for this!. Resource is definitely private tho. Update: reverted the Label change because it's potentially breaking, but kept the Resource change.
5. Test methods in the form lowerSnakeCaseOfSystemUnderTest_lowerSnakeCaseOfExpectedBehavior
6. Don't do static import on classes (import static com.google.cloud.logging.Logging.TailOption).
7. Each top-level class gets its own file (ResourceTypeEnvironmentGetterImpl)

[losalex]

In general, this looks good - thanks for your effort @bpcreech!
I just had one concern about changing labels - please take a look and let me know WDYT

[conventional-commit-lint-gcf]

🤖 I detect that the PR title and the commit message differ and there's only one commit. To use the PR title for the commit history, you can use Github's automerge feature with squashing, or use automerge label. Good luck human!

-- conventional-commit-lint bot
https://conventionalcommits.org/