Shareable makefile and rake tasks for extracting translations in hammer

Past two hammer-cli and hammer-cli-foreman releases we experienced
some issues with merging translations, fuzzy matching or generating
.mo files, which caused us to update the rake tasks and Makefile we
use for extracting strings and merging translations. Probably all
translated hammer plugins contain a copy of the Makefile from hammer
core from the time the plugin was created and rarely update it so most
of them is most likely affected with some of that issues too. It's
also not very efficient to update all the plugins when there's a need
for a change in the process.

Therefore I created a common Makefile.def and rake task that can be
included from a hammer plugin:

I'd appreciate if plugin authors could test and review the change.

I'll send one more announcement once the change is released and ready
for consumption.

Thank you