Add correct jar mime type

[noeppi-noeppi]

According to https://www.iana.org/assignments/media-types/application/java-archive, the MIME type for jar files is application/java-archive. However, currently, engrampa only lists application/x-java-archive in its desktop file. This pull request adds the application/java-archive MIME type as well as the other two deprectaed aliases listed in the document above (application/jar and application/jar-archive) to the list.

[zhuyaliang]

@cwendling @lukefromdc Do we need to accept this PR? I am not familiar with jar type files

[lukefromdc]

I also have no test files for this, but I suspect these may be quite common for Java developers and possibly users