Signal `CatalogSource` Ready status

[everettraven]

We should modify the CatalogSource CRD to signal in it's status, when a CR is ready.

Definition of ready: When the CatalogSource controller is done parsing the content of the image,and the content is available on cluster, ready to be queried by clients.

[joelanford]

In addition, we should update the status with all the different scenarios:

• currently unpacking (with any relevant messages about the unpacking progress)
• unpacking failed (with the reason it failed)

And we should use standard Conditions []metav1.Condition in the status.

[everettraven]

@joelanford I created a separate issue for setting status based on errors and other states and improving the error handling here: #6