misc: cleanup Dockerfiles

* Cleanup: Use spaces instead of tabulation

* Cleanup: Reduce layers

* Cleanup: Homogeneise wget syntax

* Cleanup: Use binary GPG key format

jicofo/Dockerfile

@@ -2,12 +2,10 @@ ARG JITSI_REPO=jitsi
 ARG BASE_TAG=latest
 FROM ${JITSI_REPO}/base-java:${BASE_TAG}
 
-RUN \
-	apt-dpkg-wrap apt-get update && \
-	apt-dpkg-wrap apt-get install -y jicofo && \
-	apt-cleanup
+RUN apt-dpkg-wrap apt-get update && \
+    apt-dpkg-wrap apt-get install -y jicofo && \
+    apt-cleanup
 
 COPY rootfs/ /
 
 VOLUME /config
-