Make terminator and initializer VirtualWorkspace URLs distinguishable

[SimonTheLeg]

Currently the VirtualWorkspaceURLs for both terminators and initializers are packed together in a singular field, requiring end-users to parse them out correctly using string matching on "terminating" and "initializing". This can be a bit confusing

status quo

  virtualWorkspaces:
  - url: https://127.0.0.1:7444/services/initializingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc
  - url: https://127.0.0.1:7444/services/terminatingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc
  - url: https://127.0.0.1:7445/services/initializingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc
  - url: https://127.0.0.1:7445/services/terminatingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc

Currently there are two ideas to resolve this:

1. We could move both of them into their separate EndpointSlice Type, similar to how we do it with ApiExportEndpointSlice

2. We could introduce a field "type" on the virtualWorkspaceURL to make them distinguishable

     - url: https://127.0.0.1:7444/services/initializingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc
       type: initializing
     - url: https://127.0.0.1:7444/services/terminatingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc
       type: terminating
     - url: https://127.0.0.1:7445/services/initializingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc
       type: initializing
     - url: https://127.0.0.1:7445/services/terminatingworkspaces/ba4lih084zcuemhg:alpha-ppcyckaokc
       type: terminating