Repair minor problems in self-release

Add missing underscore in two echo commands in release-job.sh.
Move comment for shellcheck disable onto separate line in lf-env.sh.
Extend documentation of the container self-release process.
Exclude lf-rtdv3.rst from WriteGoodLintBear coala processing.

Change-Id: Idc363f9e2b0a6189283b8dd0385926b870a2db27
Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>