Velero: Add bulk deletion support to ark restore delete

[carlisia]

Modify ark restore to bulk delete restores, so that a user could do bulk deletes using --all or -l / --selector. This would be in line with kubectl.

Examples:

• delete restores named "restore-1" and "restore-2"
  ark restore delete restore-1 restore-2

• delete all restores with label foo: bar
  ark restore delete --selector foo=bar

• delete all restores
  ark restore delete --all

This is related to this issue: https://github.com/heptio/ark/issues/295

[ncdc]

Need to resolve
https://github.com/heptio/ark/issues/748#issuecomment-411474132

[carlisia]

Edited the description, please check!

[shubheksha]

I'd like to take a stab at this!

[rosskukulinski]

@carlisia To clarify: is -l an alias for --all or --selector?

Kubectl behavior uses -l an alias for --selector and I think we should match that.

-l, --selector='': Selector (label query) to filter on, not including uninitialized ones.

[rosskukulinski]

Hi @shubheksha! Thanks for volunteering to tackle this and #748. You'll find that they're both likely similar to https://github.com/heptio/ark/pull/745.

Please read over https://github.com/heptio/ark/blob/master/CONTRIBUTING.md and you're welcome to join us in the #ark-dr channel on the Kubernetes slack server.

[ncdc]

@rosskukulinski -l is short for --selector. I'll adjust the description.