PiGro Updated Install Method

[actionschnitzel]

I have updated the description. I hope my English makes sense. Additionally, I have updated the icons. I created the install script following the example of the FreeTube installer, and it worked for me.

Regarding the uninstaller, I'm not entirely sure; I'm not a Bash-Ninja...
Since the old installation method clones to HOME, and the new DEBIAN PACKAGE installs to /opt, the old path must be deleted.
DEBIAN PACKAGE modified as discussed:
closes #2490

Testing process:

1.Existing PiGro installation via Pi-Apps
2.Replace ~/pi-apps/apps/PiGro
3.PiGro Uninstall (GitHub) (worked)
4.PiGro install (DEB) (worked)

[theofficialgman]

Regarding the uninstaller, I'm not entirely sure; I'm not a Bash-Ninja... Since the old installation method clones to HOME, and the new DEBIAN PACKAGE installs to /opt, the old path must be deleted. DEBIAN PACKAGE modified as discussed: #2490

I took the liberty of simplifying that. There is no need to check if the folders/files exist before attempting to delete them. the f option from rm already does that. It is a no-operation with exit code 0 if there is nothing to do.

In theory, on upgrades, the old uninstall script gets run and that folder in home and the old .desktop file would already be removed, but sometimes we see strange things from users so you never really know. For a change like this we generally put it in both the install and uninstall script which is what I have done.