moved dockerfile for rigctld container build

rigctld/Dockerfile

@@ -0,0 +1,20 @@
+# build rigctld
+
+FROM debian:latest
+
+RUN mkdir src
+# this might be too much, but let's try it
+RUN apt update
+RUN apt install -y libconfig-dev autoconf libtool git gcc g++ make cmake libudev-dev libreadline-dev libusb-1.0-0-dev libavahi-common-dev libavahi-client-dev
+
+# build hamlib/rigctld
+RUN <<EOF
+cd src
+git clone https://github.com/Hamlib/Hamlib.git
+cd Hamlib
+./bootstrap
+./configure
+make
+EOF
+
+CMD /bin/rigctld