Stop apply --enable-state deleting resources whose metadata changed - #148

TL;DR: apply --enable-state no longer deletes a resource when its metadata changes.

What & why

With --enable-state, apply works out what to delete by matching each resource in the state against the files. It matched by all of a resource's metadata, so changing a Topic's metadata.description, or giving it a first label, made the applied topic look removed: apply deleted it and created it again — its messages are lost. Any metadata edit to a stateful resource can do this, and nothing in the output says the delete is a recreate (a dry run shows one delete and one update).

Changes

• The state tells resources apart by kind, name and parents — the path and query parents its kind needs, a Gateway resource's vCluster, an interceptor's scope (Catalog.StateIdentity) — passed in where the state is loaded. Without it the old comparison is kept.
• A resource applied again replaces its stored entry, so the state holds its current metadata.

Notes

• Checked against a local Console (main image): adding a description to an applied topic is now Updated, where it was deleted and recreated, and the description reaches the Console.
• Further apply fixes are stacked on this one (Plan creates with diffs, and apply the deletes of an emptied folder #149); the descriptionFile fix is Send a topic's descriptionFile as metadata.description #146.