[Tree Status] Update all references in Skia repo to tree-status

* Mainly updates to documentation.
* Fix some comments in PRESUBMIT.py.
* Delete tools/lua/trigger_ct_lua. It has not worked in many years.

Bug: skia:9962
Change-Id: If6f58f173f2c8bd3fc9bdfc4db440f42489fee08
Docs-Preview: https://skia.org/?cl=274597
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/274597
Commit-Queue: Ravi Mistry <rmistry@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
10 files changed