Doesn't matter much since the keywords is really only used in software managers/browsers where we don't publish Cura, but if someone is to make a package (like people did for Arch and Debian) this should get Cura a few more hits.
```
cura.desktop: error: (will be fatal in the future): value "cura-icon.png" for key "Icon" in group "Desktop Entry" is an icon name with an extension, but there should be no extension as described in the Icon Theme Specification if the value is not an absolute path
```
__Solution:__ Remove `.png`. __PLEASE NOTE__ that for this to work, cura-icon.png must be located in one of the directories in which desktops search for icons, such as `/usr/share/icons/hicolor/128x128/apps/`. Please make sure it ends up there (also in the AppImage, too.)
```
cura.desktop: error: value "application/sla;application/vnd.ms-3mfdocument;application/prs.wavefront-obj;image/bmp;image/gif;image/jpeg;image/png" for string list key "MimeType" in group "Desktop Entry" does not have a semicolon (';') as trailing character
```
__Solution:__ Add `;`
Reference:
https://travis-ci.org/AppImage/AppImageHub/builds/266072586#L538-L539
Adds support to install Cura to an alternative path, while generating a correct .desktop file for it.
* Renaming cura.desktop to cura.desktop.in
* CMAKE: Generate .desktop from .desktop.in
* Replace hardcoded paths with FULL_PATHs
* Tell CMake to generate cura.desktop
* CMake: Set full paths for .desktop generation
* It tells CMake where to find the .desktop.in is and where to store the result.
