Generate Service catalog metadata for APIs and Proxy services

[SanojPunchihewa]

Description:

In the Integration Studio, a metadata file will be created when an API or proxy service is created which is used to deploy the API or Proxy service to APIM Service catalog. Instead of creating the metadata file through VSCode plugin it was decided to generate it when creating the CAR file. To cater this requirement we need to do the following improvements,

• [x] #333
• [ ] Currently, VSCode create the swagger file only if the user use the swagger view. But since we need the swagger for the service catalog functionality, we need to create the swagger file upon API creation.

[chanikag]

After adding the feature to VS Code plugin add the relevant docs as mentioned in https://github.com/wso2/docs-mi/issues/515