Provide a views filter handler for project properties

Description of the need

This is a follow-up to #5820. That issue added a views field handler to access project properties. A filter handler would be an additional helpful feature to produce more targeted lists of projects.

Proposed solution

Create a views filter handler.

Additional information

The project properties are saved in a serialized column in the system table, which means that this filter has to take this into account. Querying a serialized column can be a bit tricky. One alternative may be to do pre-render filtering with PHP rather than a traditional Views filter that creates a WHERE clause in the sql query.

Draft of feature description for Press Release (1 paragraph at most)

Backdrop now includes a Views filter that allows site administrators to filter views of modules and themes by their properties.