ENHANCEMENT: Expose delete_from_target for supported by provider syncs

[ViacheslavKudinov]

Currently when termination of Terraform resources happens, secrets and "resources" will still remain on the target's side.

As it is supported by REST API it will be great to expose for "users" of provider to be able to set delete_from_target when they decide it is safe to have this behavior.
Moreover it is the option on Doppler UI to keep or delete secrets on the target.

So, it will be great to get option to delete secrets of target. Maybe, can be set false by default for the "safety".

[ViacheslavKudinov]

In some sense related to #65 as well

[nmanoogian]

Thanks for the recommendation, @ViacheslavKudinov! Working on this now

[ViacheslavKudinov]

Hi,
i think it was addressed by this PR #93
and is there sinse v1.9.0

[nmanoogian]

Right you are! I must have forgotten to add the "Closes" magic word to that PR. Thanks!