Add support for /usr/local/etc/app.config

[tld]

A lot of non-linux systems (*BSD, MacOS...) keep non-base config files in /usr/local/etc, and it's a also a convention to support appname.conf as a filename in these directories, rather than just appending rc.

I'm suggesting it would be good to support that in this module, as it'd allow more closely aligning the conventions supported with what's expected on some platforms.

[dominictarr]

This sounds reasonable, but I'm not familiar with these systems. Can you link me to anything that describes that convention well?

[tld]

Sorry for the slow reply, I somehow missed the notification of your upate.

FHS - Filesystem Hierarchy Standard mentions it:
http://www.pathname.com/fhs/pub/fhs-2.3.html#USRLOCALLOCALHIERARCHY

More system-specific, it's also mentioned in FreeBSDs hier(7)-man page:
https://www.freebsd.org/cgi/man.cgi?hier(7)

And mentioned in documentation of the Handbook:
https://www.freebsd.org/doc/handbook/ports-nextsteps.html

Not specific to FreeBSD though, pulling random examples from Google, we can see the same pattern in Solaris:
http://www.chadstechnoworks.com/wptech/os/how_to_configure_sudo_in_solaris.html

And MacOS:
http://sourabhbajaj.com/mac-setup/Scala/README.html