OO-1658: updated context help for archiver

src/main/java/org/olat/course/archiver/_chelp/arch-logf.html

- <br/>$r.translate("chelp.logf1")
-<br/>
-<br/>
-$r.translate("chelp.logf2")
-<br/><br/>
-$r.translate("chelp.logf3")
-<br/>
-<br/>
-$r.translate("chelp.logf4")
-<br/><br/>
-$r.translate("chelp.logf5")
-<br/><br/>
-$r.translate("chelp.info"):
-$r.contextHelpRelativeLink("course-log.html")

src/main/java/org/olat/course/archiver/_content/archiver_index.html

+$r.contextHelpWithWrapper("Using Course Tools#_datenarchivierung")
 <h4>$r.translate("index.title")</h4>
 <p>
 	$r.translate("index.intro")