Word mimetype outcome changed, after update of libreoffice.

After several updates of libreoffice the list had some changes due the
new version of libreoffice binary.

This initial implementation has several copied code from ERP5 Project which
must be removed as soon as possible. The code should be comes from
erp5.util library.

This reverts commit 1346047c.

By default it is 800px but as we normally use exported content in root ERP5 web sites smaller defaults is usually better (still it's an ugly hack).

Use encoded text convertion by default.
Do not use filter which rely on java.