[Forward-port to v13] Able to configure resource resolvers in spring assembly XML

At the moment, developers have to configure crisp resource resolvers only through repository configuration.

Some developers complained about this because from their perspectives they don't need to configure it through repository configuration at all as their deployment practice always redeploy site war anyway. As spring bean assembly xml file can refer to properties in hst-config.properites, environment specific configuration wouldn't be a problem.
They suggest it should provide an option to configure resource resolvers through spring bean assembly XML instead of only repository configuration.

[1] https://www.onehippo.org/library/concepts/crisp-api/configuring-crisp-addon.html