Convert Web Terminal Operator to depend on DevWorkspace Operator

[amisevsk]

What does this PR do?

Removes duplication of CRDs/images from DevWorkspace Operator and configures this operator to depend on the DevWorkspace Operator.

What issues does this PR fix or reference?

Part of https://github.com/devfile/devworkspace-operator/issues/407

Is it tested? How?

Simple: apply the catalogsource below which references bundles built from this PR and https://github.com/devfile/devworkspace-operator/pull/438

cat <<EOF | oc apply -f -
apiVersion: operators.coreos.com/v1alpha1
kind: CatalogSource
metadata:
  name: custom-devworkspace-demo-catalog
  namespace: openshift-marketplace
spec:
  sourceType: grpc
  image: quay.io/amisevsk/devworkspace-demo-index:dev
  publisher: Angel Misevski
  displayName: DevWorkspace + Web Terminal integration demo
EOF

Manual:

1. Add catalogsource for DWO
   1. Checkout https://github.com/devfile/devworkspace-operator/pull/438 locally
   2. Export DWO_BUNDLE_IMG and DWO_INDEX_IMG as appropriate
   3. Run make generate_olm_bundle_image generate_olm_index_image
   4. Add catalogsource: make register_catalogsource
2. Add new catalogsource for DWO
   1. Build bundle and index: make build
   2. Register catalogsource: make register_catalogsource
3. Install operator through OperatorHub UI in OpenShift. Note: there will be two options for "Web Terminal Operator". The correct one has Version 1.3.0

Screencast:

https://user-images.githubusercontent.com/16168279/119721987-d0c64480-be39-11eb-9fd9-01a5462171df.mp4

[amisevsk]

Rebased and autosquashed.