Implemented the host name auto suggestion, and added Preset feature

Dockerfile

@@ -54,7 +54,9 @@ ENV SSHWIFTY_HOSTNAME= \
     SSHWIFTY_TLSCERTIFICATEFILE= \
     SSHWIFTY_TLSCERTIFICATEKEYFILE= \
     SSHWIFTY_DOCKER_TLSCERT= \
-    SSHWIFTY_DOCKER_TLSCERTKEY=
+    SSHWIFTY_DOCKER_TLSCERTKEY= \
+    SSHWIFTY_PRESETS= \
+    SSHWIFTY_ONLYALLOWPRESETREMOTES=
 COPY --from=builder /sshwifty /
 COPY . /sshwifty-src
 RUN set -ex && \