Add support for disabling checks via a config file

Is there a configuration file argument, that can be added to the `bootlint` command, which points to a file consisting of the various bootlint adjusted rules.

For example, I'm looking to convert the following:

```
bootlint -d W005 interface/templates/*.html
```

to the following:

```
bootlint --config /path/to/ruleset.json interface/templates/*.html
```
