Publish some issues as unignorable lint issues and others as comments

[marco-c]

Issues that would break mozilla-central CI can be published as Phabricator lint issues (since they have to be fixed in order to land the revision).
Issues coming from SA tools with false positives should be published as comments, so that developers can decide to ignore them.

[marco-c]

@smacleod could we prevent landing patches which have unignorable lint issues?

[marco-c]

As we discussed recently, we could add a warning to Lando (or even prevent landing completely for unignorable issues, since they will lead to backout if landed).

[marco-c]

#418 is publishing some errors as lint issues. After we release it to prod and after a few days of usage, we can go all the way and publish all errors as lint issues (see #418 (comment)).

[marco-c]

Reopened for #25 (comment), to track publishing all errors as lint issues.

[La0]

I'm adding a TC secret switch to enable/disable error publication, and will publish all errors as lint results.