CI/CD: Update Workflow to Support New Proxy [Sandbox]

**Description:**

The deployment of new proxy significantly changed the structure of our runtime instance. The current implementation of CI/CD is not able to deliver updates properly. Here is the list of things that need to be supported by a new CI/CD pipeline:

- [ ] automatically upload new RAML to Exchange
- [ ] update proxy's RAML version
- [x] generate new `keystore.jks` for HTTPS connection
- [x] prior to deployment, remove `global.xml`
- [x] prior to deployment, rename `global.xml.anypoint` to `global.xml`
- [ ] update RAML specification version in `global.xml` and `pom.xml`
- [ ] deploy the app, updating Mulesoft Secure Properties based on the GH Secrets