Replace .rc script by .res resource file in order to avoid issues with windres

[wp-xyz]

Replace .rc script by .res resource file in order to avoid issues with windres (https://forum.lazarus.freepascal.org/index.php/topic,48691.msg350922.html).
Add additional high-dpi palette icons.

[dezlov]

Thanks for the changes. Looks good.

[dezlov]

For those encountering the same problem with windres prior to these changes, you need to replace \ with / in the *.rc file to fix the issue.

[wp-xyz]

The new revision is not yet available through OPM. You should give the new version a new version number and pack the files into a zip in your "archive" like you did before. Then you should update the update.json file with the storage location of the new zip. This would make the new version available for OPM installation from the "third-party repository". In order to bring it into the "official repository" you should contact forum user GetMem, the maintainer of OPM, and ask him to update the package in OPM.

[dezlov]

I sent a message to GetMem asking to update the package in the OPM repository.