feat: support setting amanda config by env variable

closes #51

server/scripts/entryPoint.sh

@@ -1,8 +1,13 @@
 #!/bin/bash
 
-amcleanup -k server
-amcheck server
-amdump server
-amstatus server
+if [ -z ${AMANDA_CONFIG} ]; then
+    echo "it set best practise to set the AMANDA_CONFIG environment variable"
+    AMANDA_CONFIG="server"
+fi
+
+amcleanup -k ${AMANDA_CONFIG}
+amcheck ${AMANDA_CONFIG}
+amdump ${AMANDA_CONFIG}
+amstatus ${AMANDA_CONFIG}
 
 exit 0