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.
Apparently, DIB is sensitive to file names, at least the package-install
feature. Let us make sure we use ironic-python-agent-ramdisk, not ironic-agent.