packaging/debian: Add debuild files

[norihiro]

Description

Add debian directory to publish the plugin on PPA.

How Has This Been Tested?

Published with a command below.

./publish-ppa.sh --commit HEAD --append libvisca --version 0.8.0-submodule1 --ppa norihiro/plugins-for-obs-studio-unstable

(publish-ppa.sh is still located on my workspace only.)

• Confirmed it works.
• Data files are missing.

General checklist

• The commit is reviewed by yourself.
• The code is tested.
• Document is up to date or not necessary to be changed.
• The commit is compatible with repository's license.