Support repeated query parameters as an array

[gwax]

Describe the problem

Use repeated query parameters for array serialization instead of encoding an array as a single parameter:

For example: query=1&query=2&query=3 instead of query=[1,2,3]

Describe the proposed solution

A StoreOption to the effect of append to indicate that modifying the searchParams should use "append" instead of "set" and should read via "getAll" instead of "get". An empty array serializes as an absence of keys and a non-empty array serializes using the encoder on each element and storing the value in repeated query parameters