Add support for partial name matching when using `name` field filtering on Python content endpoint.

[decko]

Is your feature request related to a problem? Please describe.
pulp_python content endpoint only allows exact name matching filtering. This doesn't allow users to find packages using partial names to find packages and their related ones.

Describe the solution you'd like
Have a name__contains query parameter, or be able to access the name__contains filter using the q query parameter.