* initial avahi support
This commit adds support for the Avahi advertiser with Scrypted. It also adds the s6 process supervisor to facilitate future service additions.
* universal s6
This commit attempts to fix the issue where Avahi doesn't start on non-x86_64 architectures.
* consistency updates
This commit updates the wording in certain s6 run files to be consistent.
* fix s6 overlay version argument
This commit fixes the S6_OVERLAY_VERSION argument being prematurely collected by moving it after the FROM command.
* correct shebangs
This commit corrects the shebangs of all s6 service scripts to register with s6 instead of just running under bash.
* register services with s6
This commit adds two empty files that correspond to the dbus and avahi services started by s6. Without these files, s6 does not initialize daemons to keep dbus and avahi running.
* fix permissions and shebangs
This commit fixes the permissions on the service scripts that s6 is responsible for starting. It also reverts the shebang back to bash because many script utilities aren't available when running under execlineb.
* organize added features by block
This commit organizes all added lines into separate blocks for both avahi and s6-overlay. Resolves some of koush's review comments on #323.
