mw.Uri: Add support for array parameters with explicit indexes

mw.Uri: Add support for array parameters with explicit indexes

When the new 'arrayParams' option is set, query strings like
`&foo[0]=a&foo[1]=b` will be parsed as a single parameter `foo`
containing an array, rather than two separate parameters.

The new option also affects the behavior of array parameters like
`&foo[]=a&foo[]=b`, which will be parsed as a parameter named `foo`
rather than `foo[]`, and disables array handling for parameters that
don't contain an array index at the end.

Unlike in PHP, this does not handle associative or multi-dimensional
arrays, but that may be improved in the future.

Bug: T231382
Change-Id: I48d4bb3fdf0ea7f5eb133c59bf63651ba356fc42