Correct configuration for Sphinx generation

- remove useless code in docs/conf.py
- force lfdocs-confr~=0.7.5 in etc/requirements.txt
- add funcparserlib==1.0.0a0 in etc/requirements.txt
- enforce compatible versions in others packages

Issue-ID: DOC-765

Signed-off-by: Eric Debeau <eric.debeau@orange.com>
Change-Id: I3e963dd2bdaaf5e484e1c3270674373eef3fce24
2 files changed