Leverage upper-constraints files to pin all dependencies

Leverage upper-constraints files to pin all dependencies

It leverages the latest change from lfdocs-conf and the
upper-constraints.txt now centralized in ONAP docs.
In a long run, upperconstraints.os.txt should be removed once ONAP
is synced with OpenStack.

It removes tox and setuptools from requirements as nothing depends on them
(most requirements should be removed except lfdocsconf)

Issue-ID: DOC-765

Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
Change-Id: I63da3905aa77d561b28aedc8d9b69e535852206d

Former-commit-id: 6f7fa79eaed75440f53fc0b061a7d2a0cd1a1305