kube: standardize on a `local top = self` convention

A convention is introduced to specify `local top = self` declaration at the top of an app/service/component's jsonnet, representing the top-level object. Reasoning is as following:

- `top` is more universal/unambiguous than `app`
- `top` is usually shorter than $NAME
- a conventional `top` instead of $NAME (coupled with other conventions introduced) makes app jsonnets wonderfully copy-paste'able, aiding in learning and quickly building

Change-Id: I7ece83ce7e97021ad98a6abb3500fb9839936811
Reviewed-on: https://gerrit.hackerspace.pl/c/hscloud/+/1805
Reviewed-by: q3k <q3k@hackerspace.pl>
diff --git a/app/onlyoffice/prod.jsonnet b/app/onlyoffice/prod.jsonnet
index eafde30..9d9b410 100644
--- a/app/onlyoffice/prod.jsonnet
+++ b/app/onlyoffice/prod.jsonnet
@@ -7,8 +7,8 @@
 
 {
     onlyoffice:: {
-        local oo = self,
-        local cfg = oo.cfg,
+        local top = self,
+        local cfg = top.cfg,
         cfg:: {
             namespace: error "cfg.namespace must be set",
             image: "onlyoffice/documentserver:7.0.0.132",
@@ -58,7 +58,7 @@
                             },
                         },
                         volumes_: {
-                            data: kube.PersistentVolumeClaimVolume(oo.pvc),
+                            data: kube.PersistentVolumeClaimVolume(top.pvc),
                         },
                     },
                 },
@@ -66,12 +66,12 @@
         },
 
         svc: ns.Contain(kube.Service("documentserver")) {
-            target:: oo.deploy,
+            target:: top.deploy,
         },
 
         ingress: ns.Contain(kube.SimpleIngress("office")) {
             hosts:: [cfg.domain],
-            target_service:: oo.svc,
+            target_service:: top.svc,
         },
 
         // Needed because the documentserver runs its own supervisor, and: