Add fuel installer adapter

Add fuel installer adapter

v3 -> v4:
- extract common variable refs, fold some reusable code;
- provide dummy defaults for PDFs without net_config;
- keep yamllint happy about spaces and empty lines;

v4 -> v5:
- more folding, define a macro for multiple IP address definition;

v5 -> v6:
- added MaaS network / DHCP range support;

v6 -> v7:
- removed macro, template code reverted to output style

JIRA: FUEL-275

Change-Id: Ib1cc319534d06c088b1db16a43aef663a8ada0d8
Signed-off-by: Guillermo Herrero <guillermo.herrero@enea.com>
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
(cherry picked from commit 25b2adb887b5e1cab767023476dd0ec2f02b4b59)