Bug 34169: Use jQuery validator plugin to validate amounts

Bug 34169: Use jQuery validator plugin to validate amounts

This is a first step towards more consistency and possibly supporting
multiple input formats as well in the future. It allows us to mark all
input fields for monetary values, such as prices, replacement prices,
fees etc. with a class that is linked to a check for the 'number' format
in the jQuery Validator plugin.

This is the base patch that does nothing by itself, please see
test plan in second patch.

Signed-off-by: Michaela Sieber <michaela.sieber@kit.edu>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>