feat: iOS Bindings

[ElusAegis]

PR: Integrating iOS Bindings for the EZKL Library

This PR introduces iOS bindings for the EZKL library, developed using the uniffi package. This package facilitates the generation of bindings for multiple platforms, including iOS (Swift), as well as Android (Kotlin, Java), Python, and Ruby.

Key Updates:

1. Created a new bindings module to consolidate all bindings, moving the previously existing python and wasm bindings under it.
2. Introduced a bindings/universal module containing uniffi-compatible bindings. These bindings implement most functions by reusing code from the existing wasm bindings.
3. Refactored the wasm bindings to leverage the shared code from the universal bindings.
4. Added a new script bin/ios_gen_bindings to generate iOS bindings and package them for integration into iOS projects.
5. Included a new GitHub Actions workflow .github/workflows/update-ios-package.yml to test the bindings and automatically update the iOS package with the latest bindings when a new release of EZKL comes out.

Next Steps:

We should consider migrating the iOS EZKL package under the zkonduit organization to better streamline the development process.

Future Considerations:

A larger refactor could further simplify the code by avoiding the need to use cfg(not(any(target_os = "ios", target_arch = "wasm32"))) for functions that should be excluded from the bindings. Moving such functions into a separate module would reduce the number of changes introduced by this PR and improve code clarity.

[alexander-camuto]

@ElusAegis wasm tests are currently cooked because of relative imports :)

[ElusAegis]

@alexander-camuto I think this is ready for another review

Key Updates since last review:

1. Added ios-integration-tests to be run locally, that required to patch uniffi_testing crate, which has an issue submitted to resolve this. This also required to add the build.rs file to set up correct ENV variable for the ios bindings test. Optionally, we could remove build.rs and instead force users to set this variable before running the tests.
2. Moved from using target_os = "ios" to a specific feature for ios bindings - ios-bindings. Additionally added ios-bindings-test feature for the tests. This is useful to enable some test dependencies only when testing, thus making the bindings leaner.
3. Restructured the Cargo.toml file to optimise out dependencies that are not needed for ios and wasm bindings, such as clap. Additionally, cleaned up the code, so that it would compile with --no-default-features flag, by conditinally compiling some modules only when feature ezkl is enabled (which was previously gated by target_arch = "wasm32". This is useful when we want to have as lean version of EZKL as possible, for for example ios bindings.
4. Fixed crate dependency issue for wasm tests.
5. Added ios-integration-tests and swift-package-tests to rust.yml to test the ios bindings and ios bindings package.

Next Steps:

1. To finish integration, we need to move the iOS EZKL Swift Package under the zkonduit control and correctly setup repository secrets to enable the update-ios-package.yml to function and push releases.

   Possibly, update-ios-package.yml can be integrated into release workflow.

[alexander-camuto]

@ElusAegis a few conflicts to resolve given the reusable verifier merge and then will merge in