Add support for Twilio SMS

[SuperQ]

Upstream now includes a Twilio example script.

• Add support for adding new values to the config.inc.php.
• Add variables for the Twilio example script.

[SuperQ]

I'm getting a strange build error when I try and build this locally.

STEP 4/5: RUN source /assets/functions/00-container &&      set -x &&      package update &&      package upgrade &&      mkdir -p /assets/install &&      curl -sSL -o /assets/install/v${SSP_VERSION}.tar.gz https://github.com/ltb-project/self-service-password/archive/v${SSP_VERSION}.tar.gz &&      package cleanup
/bin/sh: /assets/functions/00-container: line 1396: syntax error: unexpected "(" (expecting "done")
Error: error building at STEP "RUN source /assets/functions/00-container &&      set -x &&      package update &&      package upgrade &&      mkdir -p /assets/install &&      curl -sSL -o /assets/install/v${SSP_VERSION}.tar.gz https://github.com/ltb-project/self-service-password/archive/v${SSP_VERSION}.tar.gz &&      package cleanup": error while running runtime: exit status 2

This also errors when built from main. The line in question is here. It might be the fact that I'm using podman to build and not actual Docker.