Added option to hide warnings for fuzzy messages

The option is also hidding obsolete translations.

As proposal from https://github.com/ManageIQ/manageiq/pull/1062, we could use an option :ignore_fuzzy => true, but that one's still showing a warning message in rails log.
```
 Warning: fuzzy message was ignored.
```



Are there ever going to be warnings we care about?  I wonder if this is something we could toggle in an environment var, or something,

Thoughts?