feat: MTA resource v1alpha1 version

[Lasserich]

This PR merges the previous implementation of the MTA Provider with this CloudFoundry Provider.

Reasoning

This is done to adhere to the standards of the CloudFoundry Terraform Provider, having chosen the same path instead of creating separate providers. Beyond this reasoning there are also synergies created by re-using the same CloudFoundry client for both APIs and enabling Provider native references of the Space resource.

Example

apiVersion: cloudfoundry.crossplane.io/v1alpha1
kind: Mta
metadata:
  name: test
  namespace: default
spec:
  forProvider:
    namespace: default
    spaceRef: 
      name: my-space
    blueGreenDeploy: true
    file:
      url: <url>
      credentialsSecretRef:
        name: secret
        namespace: default
    extension: |
      _schema-version: 3.3.0
      extends: my-app
      ID: my-app.extension
      modules:
        - name: my-app-srv
          parameters:
            instances: 2

apiVersion: v1
kind: Secret
metadata:
  name: secret
  namespace: default
type: Opaque
stringData:
  user: my-user
  password: my-password
  cred: my-user:my-password

Done criteria are:

• implement MTA client
• implement MTA resource
• provide working example
• unify provider config
• unify secrets (?) -> so actually we use a docker-registry type secret for our App deployments. It does not seem feasible to use that also here for .mtar types
• support space reference parameter
• implement basic unit tests for Controller (Create, Observe, Delete) only -> Client is not managed by us so we rely on their testing etc.