restore: implement all the rest of activities restore

We should implement all these:

assignment: done
chat: done (Dan)
choice: done
data: done (Eloy) not using subplugin support. Also see MDL-22558
feedback: done (Dan)
folder: done (Dan)
forum: done
glossary:done
hotpot: requires work on module - halted
imscp: done
label: done (Dan)
lesson: done (Dan)
page: done (Dan)
quiz: done
resource (file): done (Dan)
scorm: done (Dan). Note: missing logs restore?
survey: done (Dan)
url: done (Dan)
wiki: done (Dan)
workshop: done (see MDL-19936 for details)

Legend:

implemented
reserved / in progress
todo
cannot be done yet - requires backup stuff
cannot be done yet - requires bug fixing
once implemented, has been tested and old stuff (but restore of logs) have been deleted.
restore of logs implemented