docs: Add fuller accounting of "make check" prerequisites

docs: Add fuller accounting of "make check" prerequisites

Many of the prerequisites for exercising the full "make check" test suite
have not been documented. This adds them along with a note that some tests
require elevated privileges to run.

Add an incomplete list of cross compiling toolchain packages for Debian
and trusted sources for other distros.

Add statement at the start of the document to clarify that package names
are from Debian 11.

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>