[multi-sources-removal] Drop deleted_entities system table and entities.mtime column since they were only used by the entities_modified_since api of the repository which has been dropped. Along with them, the multi-sources-etypes configuration variable and some sql queries at modification/deletion time of entities. Bon vent ! Related to #2919300

/*
 * cubicweb js mock for unit tests
 * This module defines variables and functions used in quite a few places
 * in cw js framework that can't be used or guessed without a real CW server
 */

var pageid = 'my-page-id';

function _(message) {
    return message;
}