This commit introduces the following targets:

- `format-cmake`: automatically formats any CMake source files
- `check-cmake`: checks the formatting on CMake source files
- `lint-cmake`: lints CMake source files

These are executed implicitly as part of the `format`, `check` and
`lint` targets.

The tools used to do this come from the cmake-format project:

- `cmake-format`: https://cmake-format.readthedocs.io/en/latest/cmake-format.html
- `cmake-lint`: https://cmake-format.readthedocs.io/en/latest/cmake-lint.html



Change-Id: I1706a3a42272496b6f47f3f38429bda0fb0776df
Signed-off-by: Chris Kay <chris.kay@arm.com>
Signed-off-by: Joel Goddard <joel.goddard@arm.com>
Signed-off-by: Girish Pathak <girish.pathak@arm.com>