feature: publish a Snap version of the desktop-wallet

[brenopolanski]

Snaps work across Linux on any distribution or version.

Snaps are secure. All the dependencies are isolated from the rest of system. Snaps also auto update when release a new version.

So with the snap published, the user can install it using the command:

e.g: sudo snap install ark-desktop-wallet

• See more info here: https://snapcraft.io
• Step by step to create a Snap: https://ubuntu.com/tutorials/snap-a-website#1-overview

[dav1app]

So, this is the state of the snap package.

• feat/linux-snap-package is the branch for that.
• The package is working when installed with the --dangerous since we don't have the signatures from snap. This version was compiled from the latest devel branch, so I'm just using it for testing purposes.

sudo snap install ark-desktop-wallet-linux-amd64-2.8.0.snap --dangerous 

• Created the Ubuntu One/Snapcraft account and registered ark-desktop-wallet, so we can publish the snap package. Everything is registered under ark domain.
• Also, I'm reading the docs for both snapcraft and debian to publish them in our own repo.

All of this work can be considered trivial without further discussion.