[Engineering] [Breaking Change] Scap change for deployers

[Tyler Cipriani]

tl;dr: Our beloved scap is changing to use subcommands rather than a
bunch of scripts, but the existing scripts will work for a short time.

Starting with the 3.2.0 release[0], which will hit production in the
next day or so, scap will use subcommands rather than using many
different scripts that all call the same underlying code. The scripts
(e.g., deploy, sync-file, sync-dir, sync-wikiversions.) will continue
to work as usual, but they will issue a deprecation warning until the
next release when they will disappear.

The most notable exception is the `scap` command which must be invoked
as `scap sync [message]`.

The docs are updated[1] and you can see new help output there or on
phabricator[2].

Long story short, you will now run:

    scap sync-file <path> [message]

Instead of:

    sync-file <path> [message]

This change has been cherry-picked on beta cluster and is currently live there.

<3,
Tyler Cipriani and the Deployment Working Group

[0]. https://gerrit.wikimedia.org/r/#/c/287918
[1]. https://doc.wikimedia.org/mw-tools-scap/
[2]. https://phabricator.wikimedia.org/P3027