Reland of [1].
Original CL contained some changes to --[tb]r-owners
which are not included in this CL because those changes
were reverted on [2].

- Remove GetChangeApprovalStatus and GetFilesApprovalStatus.
- Make host, project and branch part of GerritClient.
- Rename ListOwnersForFile to ListOwners.

[1] https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2587268
[2] https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2611219

Change-Id: Ife2051b8be0460d1c6bc4fbe4e3b0a571d12dafb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2616130
Auto-Submit: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@google.com>