[IMP] website: allow negative dependencies in theme customize dialog

Options and option sets can declare a data-depends attribute to specify
which options need to be enabled for them to be displayed. With this
commit, we allow specifying which options need to be *disabled* for the
same purpose (we can now do that by prefixing the options IDs with '!').

PR https://github.com/odoo/odoo/pull/29624
task-1904244