Improve config files processing

[nataliaratnikova]

The eval of $(Master --config <file> environ) and $(Master --config <file> show <agent>)
can be broken when Master does not return a well-formed bash syntax.
Particularly happens in LifeCycle configuration examples.
The reason is a missing command separator ";" at the end of lines , which are concatenated internally.
Site admins should be warned about this when writing/updating custom config files.
Also PHEDEX::Core::Config and templates need to be reviewed and corrected.