doc: Sync common content with TF-A

Some information, such as contact details, is shared between
TF-A and the TF-A Tests. Bring this into line with what is in
the TF-A repo.

Change-Id: I910e229a93da67c85d70c633d5a4597a6a788b50
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>