* documentation and script updates trying to fix#1647
* preparations for refactoring target/bin/
* complete refactor for target/bin/
* changing script output slightly
* outsourcing functions in `bin-helper.sh`
* re-wrote linting to allow for proper shellcheck -x execution
* show explanation for shellcheck ignore
* adding some more information
* DOMAINNAME can fail to be set in postsrsd-wrapper.sh
if the container doesn’t have a proper hostname, postsrsd will fail to start
because SRS_DOMAIN is empty. Make a best effort to figure out the domain name
and provide a way to set one if needed.