Add Bazel based build

Bazel is one of the build system used in the modern software world and
especually in ML OSS projects. Support for Bazel build
would allow simpler intergration into such frameworks.

Currently supported:
* Build microkernels with required CPU micro-architecture
* Combine into common library (matmul)
* Tests compilation and execution

Signed-off-by: Anton Bondarenko <anton.bondarenko@arm.com>

Reviewed-by: Felix Johnny Thomasmathibalan <felixjohnny.thomasmathibalan@arm.com>
Approved-by: Felix Johnny Thomasmathibalan <felixjohnny.thomasmathibalan@arm.com>