fix(docs): bump up sphinx version

Set the minimum version of sphinx required to 5.3.0 and pin the
version for all the packages mentioned in requirements.txt. This is
done to resolve read-the-docs build error which needs this version
of sphinx. Also removed dependency on some unneeded python packages.

Signed-off-by: Arunachalam Ganapathy <arunachalam.ganapathy@arm.com>
Change-Id: I0638d0df20017b85d9d7c1672e848ba5d3f25c48
2 files changed