Improvement to LicensePicker component

Originally mentioned in #955

The current implementation of LicensePicker component has some major functionality and usability issues...

1. only one radio button can be selected at any time:


2. if you repetitively hit "add group" and create multiple empty groups, in some cases I found you cannot delete them after:


3. in more complex expressions with multiple groups, the top radios change the middle most logical operator which may be confusing for some:


If we look at the original implementation, it functioned much the same but had some UI features that made it more user-friendly IMO:


Specifically:

- borders around each group tells you what controls go with which group (even the buttons at very top are clear as to their effect)
- buttons instead of radio boxes (even if these are radios "styled" as buttons, they still function independently)
- not sure if the behavior described in point 2 also affected the original implementation, but it does occur in this one
- there appeared to be [some syntax checking](https://github.com/clearlydefined/website/issues/178) for the expression, not sure if this is happening in the current implementation