fix(frontend): disable rivet cloud on connect page, fix actor creation (#4538)

# Description

This change updates the actor input encoding from JSON to CBOR format and refines the branding terminology throughout the frontend. The actor creation process now encodes input data using CBOR before base64 encoding, providing better binary data support. Additionally, references to "Rivet Compute" have been updated to "Rivet Cloud" for consistency, and the provider dropdown has been simplified by removing the Rivet Cloud option from the cloud app type.

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
- [ ] This change requires a documentation update

## How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my feature works
- [ ] New and existing unit tests pass locally with my changes

Author: jog1t