Changed $Yang* generation package and name

The naming of these classes is rather unfortunate, as it starts with $
due to the requirement not to conflict with other generated classes. So
they were renemed to avoid dollar sign usage.
Also the root package for theese classes was changed from
org.opendaylight.yang.gen.v1 to org.opendaylight.yang.svc.v1.
A lot of test classes are touched in this patch but no logic were
changed there, its just providing a new path for YangModuleInfoImpl.

JIRA: MDSAL-836
Change-Id: If9e43d21063c2fc48d8adbf0ccfc2406fe760054
Signed-off-by: Oleksandr Panasiuk <oleksandr.panasiuk@pantheon.tech>
Signed-off-by: lubos-cicut <lubos.cicut@pantheon.tech>
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>