Remove libreoffice package files

Unfortunately your automatic packages only get occasional updates.

Would you mind to delete the package files for LibreOffice? I am now a co-maintainer of the package and put it in [my repo for automatic packages](https://github.com/TomOne/chocolatey-packages/tree/master/automatic/libreoffice).

I think it is better to have only one copy of a package in the repositories, otherwise it could cause discrepancies.