Move restraint wrapper into the upt/restraint package

Move restraint_wrap to upt/restraint/wrapper.

• Move the directory from restraint_wrap to upt/restraint/wrapper.
• Change filenames with restraint_xxx.py to xxx.py inside of the package (for example, from restraint_shell.py to shell.py).
• Modify all restraint test names to follow the same pattern.
• Update some descriptions.
• Use relative imports in the package.

Signed-off-by: Israel Santana Aleman isantana@redhat.com