Revert "Install erp5_jquery when adding ERP5Site."

This reverts commit 6fc1169937e4f526b87e37d223910f40704044f4.
Some test fails, please review
Revert "Move jQuerified erp5.js to erp5_xhtml_style since jQuery has become essential in ERP5."

This reverts commit 5762843fe7eb57d59c668ab011010381d7c34302.
Some test fails, please review