[Templates] Generate HTTP Client from OpenAPI

[ThuF]

Create an "OpenAPI Client" template and generate specific HTTP client form the OpenAPI metadata.

Creation of such client, for the end user should be as following:

1. Create new project
2. Create new OpenAPI file (e.g. myapi.openapi)
3. Click on the Generate option
4. Select the "OpenAPI Client" from the options list
5. Publish the generated content

Consumption of such client, for the end user should be as following:

1. Import (import { ... } from '...') the generated client into the custom code
2. Consume the client

Reference clients:

1. dirigiblelabs/client-sap-successfactors-platform
2. client-kubernetes

Related issues:

• https://github.com/eclipse/dirigible/issues/357
• https://github.com/eclipse/dirigible/issues/3791

[Demonium]

Also add the functionnalty to generate also the frontend