feat: add option explode to control how query params are handled.

[wI2L]

Behavior

With explode:"true" (default)

Foobar []string `query:"foobar"`
?foobar=1,2,3
[]string{ "1,2,3" }

Foobar string `query:"foobar"`
?foobar=1&foobar=2
"error": "binding error on field 'Foobar' of type 'XXX': multiple values not supported"

With explode:"false"

Foobar []string `query:"foobar" explode:"false"`
?foobar=1,2,3
[]string{"1","2","3"}

Foobar string `query:"foobar"`
?foobar=1,2,3
"error": "binding error on field 'Foobar' of type 'XXX': multiple values not supported"

This should continue to play nicely with the enum tag since the logic about that is handled after the extraction of the query parameters.