[FEATURE] Allow more than one company assignment, Fix broken mail sending of unsolicited applications

[FEATURE] save filters in session

See merge request !27

[TASK] Take the no_search field into consideration when generating sitemaps to avoid jobs being shown twice

[BUGFIX] Check rootline when generating sitemap

See merge request !34

[FEATURE] Add link to allow external job application URLs, some cleanup, TCA restructured a little bit