Additions to find_openssl_binary() for a new openssl version / cleanup()

This is a small cleanup of find_openssl_binary(). It tries also
to find a newer openssl version which we could need for any
new features. As stated in the comment at some point we should
decide whether we stick with our old version or rather supply
a new one. (xmpp-server is also not builtin for our 1.0.2) or
maybe find a good way (code) how to use both.

Also it looks for socat and if found it populates the according
global var.

It does a minor resort of global vars in the beginning.

Dockerfile

@@ -2,7 +2,7 @@ FROM alpine:3.11
 
 RUN apk update && \
     apk upgrade && \
-    apk add --no-cache bash procps drill git coreutils libidn curl && \
+    apk add --no-cache bash procps drill git coreutils libidn curl socat && \
     addgroup testssl && \
     adduser -G testssl -g "testssl user"  -s /bin/bash -D testssl && \
     ln -s /home/testssl/testssl.sh /usr/local/bin/ && \