Adds an environment variable DIB_ADD_APT_KEYS pointing to a folder of
apt repo GPG keys. Each key will be verified and installed with apt-key
to the apt keyring.
Change-Id: I4b15347a76aa3241e741931bb94f17598641ae42
Since we are using bash syntax in some of the element fragments,
we should make sure we use bash for all of them, so that things don't
break on systems where /bin/sh != /bin/bash.
Change-Id: If2f043c57aa4e1492b7f9839213ef6123f683612
This includes the install-packages implementation for dpkg, apt http proxy
config, daemon blocking and unblocking.
Change-Id: I8f159021d2b223d7003cec067de3aa605ad06974