doc: Fix various typos

In addition to regular typos, update the spellings used for various references:

  * bitbake -> BitBake
  * kubernetes -> Kubernetes
  * licence -> license

Issue-Id: SCM-4397
Signed-off-by: Richard Neill <richard.neill@arm.com>
Change-Id: I536bb3aab6ec49a1342caa47acabc09e695af14e