Allow execution as root **(STRONGLY DISCOURAGED)**.

Running as root exposes the user to potentially catastrophic file
system corruption and damage — e.g., if the user accidentally points
the root of the session directory to a system required point, this
directory and all underlying elements will be deleted upon job
completion, thereby rendering the system inoperable.

It is recognized that some environments (e.g., containers) may require
operation as root, and that the user accepts the risks in those
scenarios. Accordingly, one can override PRRTE's run-as-root
protection by providing one of the following:

* The "--allow-run-as-root" command line directive

* Adding **BOTH** of the following environmental parameters:

     * "PRTE_ALLOW_RUN_AS_ROOT=1"

     * "PRTE_ALLOW_RUN_AS_ROOT_CONFIRM=1"

Again, we recommend this only be done if absolutely necessary.
