Add Modal deployer flavor

[strickvl]

Contact Details [Optional]

No response

Feature Description

We currently support Docker, AWS and GCP deployers via the new stack component.

We can use the logic from the Modal Step Operator update (see #3733 for more) to implement a deployer flavor to support pipeline deployments using Modal infrastructure.

Problem or Use Case

No response

Proposed Solution

No response

Alternatives Considered

No response

Additional Context

No response

Priority

None

Code of Conduct

• I agree to follow this project's Code of Conduct