Further clean-up in osmo-sgsn -> osmo-gbproxy migration

* fix manuals builds, including vty reference generation
* fix vty tests
* remove manuals from osmo-sgsn
* update .gitreview
* update osmoappdesc.py

Related: OS#4992
Change-Id: I80439ab0d21a3fb33f38da42acbfe3fbb0941b91
diff --git a/.gitreview b/.gitreview
index 560ddef..06de549 100644
--- a/.gitreview
+++ b/.gitreview
@@ -1,3 +1,3 @@
 [gerrit]
 host=gerrit.osmocom.org
-project=osmo-sgsn
+project=osmo-gbproxy