Move adagios/media/externals into a sub-module

[palli]

This patch removes all third party javascript dependencies from adagios.

I created a new repository github.com/opinkerfi/adagios-dependencies and added adagios/media/externals as a sub-module.

This makes the adagios repository cleaner, and can facilitate for more manageable bower integration in the future.

Please review and give feedback.

[palli]

Caveats with this patch:

Existing developers need to run the following:
git submodule init
git submodule update

Or simpler, when cloning a new adagios repo from github use:
git clone http://github.com/opinkerfi/adagios --recursive

[palli]

Any comments, from @pall-valmundsson or @tomas-edwardsson ?

[titilambert]

@palli I think we have to remove the .git file from the submodule root folder in debian packaging

[tomas-edwardsson]

@titilambert can you confirm that the deb packaging change is needed? I'm quite sure that rpm packaging also needs to be updated although I don't see anything needing to be changed in the adagios source.

Other than that I think we should merge and try this out. I see a definite benefit for developers not working on the javascript side to be free from thinking about javascript dependencies like npm and bower.

If this becomes akward to work with later down the road we can always change how we do this.

I've done some rudamentary tests and I see no change in functionality.