Added support for RustRover EAP and generic support for EAP

[SkoZombie]

I wanted to try RustRover but they only have an EAP and are thus not currently supported by this PPA.

I created a basic package named 'rustrover-eap' to differentiate it from what will likely come out in the future named 'rustrover'. I used the official SVG, added a "EAP" overlay, and saved a 2000x2000 PNG given that's how the icon for pycharm-professional was.

I updated update-packages so that it will check the package.json for a "eap": true entry allowing other eap packages to be easily added in future alongside releases. Given that EAP releases often have the same version number listed, EAP packages will instead look to 'build' to find their version number.

Other EAP's could be added in a similar manner, eg. pycharm-professional-eap. This would help address: #55, #54, #24, and #16

I tested on my Linux Mint 21.2 system and the packages built seem to install and work properly. I left out the built deb packages so it wouldn't interrupt your CI pipeline and figured you'd want to test anyhow.

[SkoZombie]

I double checked, the EAP version numbers are compared correctly by dpkg:

$ dpkg --compare-versions 233.10527.212 gt 233.8264.22; echo $?
0

[JonasGroeger]

Let's goo :rocket:

[JonasGroeger]

We should probably add the EAP version to the readme.