Request: Add option to store array params as comma-separated list

[nico-martinucci]

There seem to generally be two accepted methods of storing arrays in params:

?foo=bar&foo=qux

...and...

?foo=bar,qux

This library currently uses the former, but other backend filtering libraries assume params will becoming in formatted like the latter. Would be great to have either a different param type or some sort of option to store array params in the latter format for this purpose.

[pbeshai]

Try using DelimitedArrayParam for this use case