[ci] pre-commit: add check-jsonschema, other hooks #7469

Contributes to #7470

• adds check-jsonschema, to help identify mistakes in the dependabot.yml and .readthedocs.yaml files (these are sometimes hard to catch in the limited feedback from those services)
  


• adds several other pre-commit/pre-commit-hooks hooks, including some enforcing stricter handling of executable markers on files

Fixes these:

R-package/DESCRIPTION: marked executable but has no (or invalid) shebang!

tests/cpp_tests/test_common.cpp: marked executable but has no (or invalid) shebang!

.ci/lint-r-code.R: marked executable but has no (or invalid) shebang!

R-package/configure.win: marked executable but has no (or invalid) shebang!

And these:

.ci/test-python-oldest.sh: has a shebang but is not marked executable!

.ci/check-python-dists.sh: has a shebang but is not marked executable!

docs/build-docs.sh: has a shebang but is not marked executable!

docs/conf.py: has a shebang but is not marked executable!