installer: fix how collection of in memory app configs is created (#74)

Was allocating non empty slice before, which followed by appends
would leave nil-s at the beginning of the slice.

Co-authored-by: Giorgi Lekveishvili <lekva@gl-mbp-m1-max.local>
diff --git a/core/installer/values-tmpl/headscale-user.cue b/core/installer/values-tmpl/headscale-user.cue
index 5265613..fb38f8b 100644
--- a/core/installer/values-tmpl/headscale-user.cue
+++ b/core/installer/values-tmpl/headscale-user.cue
@@ -5,6 +5,7 @@
 	}
 }
 
+name: "headscale-user"
 namespace: "app-headscale"
 
 images: {}