Add better palemoon icon
Fix palemoon package/make it conform with the repository guidelines

Things made in this commit:

* Indentation of nuspec and ps1: 2 spaces
* Remove UTF-8 BOM from nuspec, add BOM to ps1 file
* Clean up Ketarin job, remove unnecessary variables
* Fix 64-bit URL to use the mirror and not FossHub, which would require
additional steps to obtain the download token
* A more reliable regex to obtain the version (previously it tried to
download the android version, which resulted in a 404).
* Match the package ID with the Ketarin job <Name>
* Update <iconUrl> to use the new icon
* Remove obsolte autoit-script and the related code in ps1