Notify JCommune about removal of section

While removal of section we need to send an HTTP DELETE request to JCommune:
http://{jcommune_url}/sections/{id_of_section}
Note that if something is wrong while sending of the request, we shouldn't remove anything from database and an appropriate error message should be shown to user.
Also note, that URL for JCommune should be taken from here: POULPE-367 If nothing is set, an error message should appear saying that he has to set respective property in component configuration.