[ Feature ] Contains Filter Option

[PhoneDroid]

Not quite sure how to best test it since the
manager ignores the local addons manifest ..

Added the metadata to Polyhedra and it seems to work ( Preview 2 )

Adds a new filter option ( Contains ) that currently only
has one option ( No generated content ) that allows to
explicitly search for addons that declare they don't
contain any generated content.

This option - unlike the rest - actually behaves as the UI
suggests, as a checkbox, not sure why the other radio groups
use checkboxes O.o ?

On purpose does not add another state in the name
of the dropdown, just adding more and more to that
doesn't seem like a good idea.

To make this option useful I'd submit PRs to the various addon
repositories to declare if / not they contain generated content.

Preview

Manifest

<contains generated_content = 'true' />
<contains generated_content = 'false' />

[chennes]

Overall looks good. Probably want to go with sentence case for the UI element to match all the others (at least, I think that's what the DWG settled on...). We're also going to want to write up some guidelines we can refer to when authors inevitably ask what it means. Do you have ideas for other "contains" elements that would make sense?

[PhoneDroid]

@chennes
Updated casing.
I'd add that information to the manifest wiki entry.

About other uses:

• Maybe something along the lines of experimental, since there is no definitive way to ascertain that from versioning and other information
• If we make the filter category more general along the lines of content flags, we could also add stuff like No external setup ( Some addons require stuff to be installed on the users system by hand )
• No online connectivity