This commit allows a table of script-opt overrides to be passed to
`mp.input.get()` and `mp.input.select()`, which console.lua will use
instead of the its own.
To minimise required changes, metatables are used to allow console.lua
to seamlessly fall back on the original script-opts if the client does
not provide an override.
To prevent exceptions, the incoming opts must be of the same type.
CogentRedTester