Meta: Add .pre-commit-config.yaml

This pre-commit config is quite simple: all it does for now is running
the already existing Meta/lint-ci.sh script to ensure no changes that
won't pass the CI linting step are committed.
Consequently pass_filenames is set to false, as these scripts will
determine which files to check themselves - should this ever become a
performance bottleneck, we can update them to accept an optional list of
filenames.

It should be noted that using pre-commit for Serenity development is by
no means a requirement, but doing so may decrease the number of CI
builds failing due to forgotten license headers etc. - especially if
you're pushing to `master` directly, rather than going through pull
requests *hint hint*.

For info how to install & use pre-commit, see https://pre-commit.com/.

Fixes #2365.

.pre-commit-config.yaml

@@ -0,0 +1,8 @@
+repos:
+  - repo: local
+    hooks:
+      - id: meta-lint-ci
+        name: Running Meta/lint-ci.sh to ensure changes will pass linting on CI
+        entry: bash Meta/lint-ci.sh
+        language: system
+        pass_filenames: false