Runtime: Support multiple runtime elements

[thewahome]

Is your feature request related to a problem? Please describe the problem.

Multiple runtimes are needed to support multiple scenarios built on a single TypeSpec file that will emit multiple OAS files. We need separate OAS files to support more than one functions/scenarios built on the same endpoint.

Describe the solution you'd like

Since Typespec emits multiple OASs, Kiota should have the ability to accept multiple descriptions and add them to the same plugin .

Kiota should organize multiple GET, PUT, POST, etc... methods as necessary so no two OpenApi files define more than one method type per OpenApi file. In other words, only one METHOD type per file per endpoint, but a single file can have a GET, PUT, POST, etc....

Additional context

The Typespec issue referenced is: https://github.com/microsoft/typespec-copilot-skills/issues/103

Acceptance Criteria

• Kiota can accept more than one OAS
• Kiota should use the multiple OAS files to generate a plugin by populating multiple runtime elements