Add the packaging metadata to build the parity-bitcoin snap

[come-maiz]

This package will let you publish the latest parity-bitcoin in the Ubuntu store, and from there reach many users on all the supported Ubuntu versions, and more Linux distributions in progress.

[parity-cla-bot]

It looks like @ElOpio signed our Contributor License Agreement. 👍

Many thanks,

Parity Technologies CLA Bot

[come-maiz]

Just like with parity, I think that snaps would be a perfect way to automate the delivery of up-to-date versions to all your Linux users. If you haven't read about snapcraft before, you can go to http://snapcraft.io/

To test this in an Ubuntu 16.04 machine:

$ sudo apt install git snapcraft
$ git clone https://github.com/elopio/parity-bitcoin
$ cd parity-bitcoin
$ git checkout snapcraft
$ snapcraft
$ sudo snap install *.snap --dangerous
$ parity-bitcoin --print-to-console

(The --dangerous flag is because the snap that you build locally is not signed by the store. Once you push it to the store, your users will just have to do $ sudo snap install parity-bitcoin)

If you have any questions, please let me know.

[debris]

thanks @ElOpio !

[come-maiz]

Thanks to you for the merge @debris !
Now you can go to https://build.snapcraft.io/ and configure the continuous delivery to the edge channel in the store. We can tell your contributors and the ubuntu community to test it. It would probably be better to use the same account used to publish parity, which I think was set up by @General-Beck.