Migrate grc blocks from xml to yaml

Convert the blocks using cmdline_converter.py script from
https://gist.githubusercontent.com/haakov/4228ff6a14486641add538483093e86b/raw/c861a840e31182ace2e74f5425e356cb4f8b183a/cmdline_converter.py

Change-Id: Iee5c611a2e100bd2fdf487611a867dc937d8c292
diff --git a/grc/misc_utils/gsm_message_file_sink.block.yml b/grc/misc_utils/gsm_message_file_sink.block.yml
new file mode 100644
index 0000000..e83669a
--- /dev/null
+++ b/grc/misc_utils/gsm_message_file_sink.block.yml
@@ -0,0 +1,23 @@
+# auto-generated by grc.converter
+
+id: gsm_message_file_sink
+label: Message File Sink
+
+parameters:
+-   id: filename
+    label: Destination file
+    dtype: file_open
+    default: /tmp/output.msg
+
+inputs:
+-   domain: message
+    id: in
+
+templates:
+    imports: import grgsm
+    make: grgsm.message_file_sink(${filename})
+
+documentation: |-
+    This block stores incoming gsm messages to a file.
+
+file_format: 1