install/uninstall option in menu for Independent Binary #7

This feature depends on whether an Independent Binary is offered or not. An Independent Binary is a executable of EZ-Bkup that is designed to be used outside of a package manager like the OS package manager or flatpak.

Something like flathub and flatpaks makes discovery of packages easy, but likely adds overhead in various forms. Having an Independent Binary would be more work for ITwrx, assuming in-addition-to flatpak or other packages, but would provide a version of EZ-Bkup that is usable as designed. In other words, not bogged down by flatpak resource requirements and latency (assumed, at the time of writing). Nim produces a small binary file size with minimal cpu and ram usage (~70MB ram and 748.6KB binary size, at time of writing. Nim v2 should be even better in both resource usage and performance) and low graphical latency. If a flatpak version is detrimental in this regard, we may need to offer our own Independent Binary for people who would prefer to use it (like maybe ITwrx). :)

This issue is for an "install"/"uninstall" link to be shown in the app menu depending on current installed state. As it sounds, it would allow easy install and uninstall of EZ-Bkup to the OS /usr/local/bin and /usr/local/share dirs as well as placing a .desktop file in /usr/share/applications and an app icon (wherever that goes).

The Independent Binary may be released prior, or at the same time, as the (possible) flatpak release. If so, the installer feature is mandatory, and should be added to the public beta milestone and marked 'accepted'.

The possible flatpak version is on the backburner for now. A graphical installer binary and EZ-Bkup binary are expected to be included with the Supporter Release available through the upcoming EZ-Bkup website. Source code will be hosted here for people who want to review it, build it themselves, or can't afford to financially support the project. Updates for compatibility with the GUI installer are included in 0.9.8.