✨[Feature] Improve Integer Range Specification for `Input` class

[gs-olive]

Adding FX support for specifying integer range + adding lowering pass to support int64 inputs with automatic casting.

1/2 MVP + Phase 1 of RFC #1425

See RFC for details.

[gs-olive]

Addressed by PR #1551, Phase 1 already exists as discussed in #1425 (reply in thread)

[Christina-Young-NVIDIA]

Also a duplicate of 1531.