Use named imports across all Compact contracts

[0xisk]

Currently, modules are imported without named imports

import "../security/Initializable" prefix Initializable_;
// usage:
Initializable_initialize();
Initializable_assertInitialized();

We should explore using named imports instead, which would be more explicit and idiomatic:

import { initialize, assertInitialized } from "../security/Initializable";
// usage:
Initializable_initialize();
Initializable_assertInitialized();

Originally posted by @emnul in #190 (comment)

[JPier34]

Hi! I'd like to work on this issue. Before starting, I have one question to make sure I'm on the right track.
Looking at the example in the issue description, the call sites still show Initializable_initialize() after switching to named imports, which I'm assuming is a typo and the intent is for them to change too.
If that's correct, there's a naming conflict to address: Ownable, FungibleToken, NonFungibleToken, MultiToken, and ZOwnablePK all export their own initialize circuit, which would clash with the imported initialize from Initializable. The compiler does support aliased imports (e.g. import { initialize as Initializable_initialize } from "../security/Initializable"), so one option would be to use those. Alternatively, I could rename the call sites to use unqualified names and restructure accordingly — but that would be a larger change.
Which approach would you prefer?
Happy to proceed once I get your feedback.