fix: support array of 1 for query parameter arrays (round 2)

[mnahkies]

#220 got a bit off-track with scope creep.

this PR takes a similar approach, but for internal use only

• detects query parameters with array type schemas
• adds an internal annotation to indicate these need preprocessing
• applies a z.preprocess to coerce an individual value to an array of 1 element, before parsing with the array schema
• for joi we resort to a pretty hacky wrapping of the schema with a object that does the preprocessing, as the joi extension API didn't work as I'd expected it to.

will continue experimenting with making this a more generally useful feature for handling things like parsing date-time strings to be a Date, etc, separately.

relates #217

Testing Notes
Need to improve automated test coverage still, but manually tested on a running server:

• No query params
• 1 element
• 2 elements
• 2 elements, 1 element

and it seems to be working correctly.

listening on http://127.0.0.1:3000
query { query: {} }
query { query: { statuses: [ 'complete' ] } }
query { query: { statuses: [ 'complete', 'incomplete' ] } }
query { query: { statuses: [ 'complete', 'incomplete' ] } }
query { query: { statuses: [ 'complete', 'incomplete' ], tags: [ '123' ] } }