When a tab was being deleted, for instance, the last block that got
deleted would cascade to delete its parent tab, even though the
`DeleteTab` function was already going to do this. This would produce DB
collisions that would put the app into a bad state. Now we pass a
`recursive` flag that is used to determine whether to perform the
recursive close of the parents.
Also updates `DeleteWorkspace` so that named workspaces will always be
deleted if they're empty, even if `force` is false
Updates `DeleteBlock` to close its parent tab if the tab has no more
blocks. This will also cascade to close the workspace if it no longer
has any tabs, same for window.
I had to move some block-related functionality around on the backend.
This fixes a bug where closing the active tab would clean up the closed
tab view before switching to an un-closed tab view, putting the window
into an unrecoverable state. This also moves around some of the CloseTab
logic so that it's more standardized and reduces unnecessary
frontend-backend comms and DB writes
