First, this change preconfigures IPA to use a configdir. This will
permit deployers to add or modify IPA configuration in elements.
This change was a prerequisite to adding additional DIB elements
which require configuration.
Additionally, this adds a DIB element to configure TLS support for
IPA's API. If added to a ramdisk build with no configuration, it
will create a self-signed certificate and configure IPA to use it.
It also exposes various environment variables to allow deployers
to use preexisting certificates or CA files.
Change-Id: Ibf88937766fa32f72b90ca81f9e8fba3515b6e33
79715dd750