Add a pre-commit hook to check for large files

This checks there are no large files being committed, which aren't
stored in git-lfs.

.pre-commit-config.yaml

@@ -3,6 +3,10 @@ repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v5.0.0
     hooks:
+      - id: check-added-large-files
+        args:
+          - --maxkb=1024
+          - --enforce-all
       - id: check-case-conflict
       - id: check-executables-have-shebangs
       - id: check-json