Provide an AppImage

[probonopd]

Is your feature request related to a problem? Please describe.
It is harder to download and run polo than need be. Especially to just quickly try it out without touching anything on the system.

Describe the solution you'd like

Providing an AppImage would have, among others, these advantages:

• Applications packaged as an AppImage can run on many distributions (including Ubuntu, Fedora, openSUSE, CentOS, elementaryOS, Linux Mint, and others)
• One app = one file = super simple for users: just download one AppImage file, make it executable, and run
• No unpacking or installation necessary
• No root needed
• No system libraries changed
• Works out of the box, no installation of runtimes needed
• Optional desktop integration with appimaged
• Optional binary delta updates, e.g., for continuous builds (only download the binary diff) using AppImageUpdate
• Can optionally GPG2-sign your AppImages (inside the file)
• Works on Live ISOs
• Can use the same AppImages when dual-booting multiple distributions
• Can be listed in the AppImageHub central directory of available AppImages
• Can double as a self-extracting compressed archive with the --appimage-extract parameter
• No repositories needed. Suitable/optimized for air-gapped (offline) machines

Here is an overview of projects that are already distributing upstream-provided, official AppImages.

If you have questions, AppImage developers are on #AppImage on irc.freenode.net.

Describe alternatives you've considered
The .run file - but it seems to change things in the system.

[Xurel]

Would be nice! It then would also work on Solus!

[Vistaus]

Would be nice! It then would also work on Solus!

It already works on Solus, either by compiling it or using the installer. But an AppImage would be easier, though.