Use the installer.sh from the source tarball

This redesigns how update works. installer.sh now rebuild the package,
stops the old code and starts the new code. Importantly, it does not
download the new package, this is left to the caller. cloudron-setup
downloads the code and calls installer.sh of the downloaded code.
Same goes for updater.sh. This means that installer.sh itself is now
easily updatable.

Part of #152

baseimage/initializeBaseUbuntuImage.sh

@@ -2,9 +2,6 @@
 
 set -euv -o pipefail
 
-readonly USER=yellowtent
-readonly USER_HOME="/home/${USER}"
-readonly INSTALLER_SOURCE_DIR="${USER_HOME}/installer"
 readonly PROVIDER="${1:-generic}"
 
 readonly SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
@@ -16,11 +13,6 @@ function die {
 
 [[ "$(systemd --version 2>&1)" == *"systemd 229"* ]] || die "Expecting systemd to be 229"
 
-echo "==== Create User ${USER} ===="
-if ! id "${USER}"; then
-    useradd "${USER}" -m
-fi
-
 export DEBIAN_FRONTEND=noninteractive
 
 echo "=== Upgrade ==="
@@ -38,7 +30,6 @@ echo "deb https://apt.dockerproject.org/repo ubuntu-xenial main" > /etc/apt/sour
 apt-get -y update
 apt-get -y install aufs-tools linux-image-extra-$(uname -r) linux-image-extra-virtual
 apt-get -y install docker-engine=1.12.5-0~ubuntu-xenial # apt-cache madison docker-engine
-usermod "${USER}" -a -G docker
 
 echo "=== Enable memory accounting =="
 sed -e 's/^GRUB_CMDLINE_LINUX="\(.*\)"$/GRUB_CMDLINE_LINUX="\1 cgroup_enable=memory swapaccount=1 panic_on_oops=1 panic=5"/' -i /etc/default/grub