msg ROS2 compatibility, microdds_client improvements (timesync, reduced code size, added topics, etc), fastrtps purge

- update all msgs to be directly compatible with ROS2
 - microdds_client improvements
   - timesync
   - reduced code size
   - add to most default builds if we can afford it
   - lots of other little changes
 - purge fastrtps (I tried to save this multiple times, but kept hitting roadblocks)

Tools/msg/generate_msg_docs.py

@@ -0,0 +1,103 @@
+#!/usr/bin/env python3
+
+"""
+Generate docs from .msg files
+"""
+
+import os
+import argparse
+import sys
+
+
+def get_msgs_list(msgdir):
+    """
+    Makes list of msg files in the given directory
+    """
+    return [fn for fn in os.listdir(msgdir) if fn.endswith(".msg")]
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description='Generate docs from .msg files')
+    parser.add_argument('-d', dest='dir', help='output directory', required=True)
+    args = parser.parse_args()
+
+    output_dir = args.dir
+    if not os.path.isdir(output_dir):
+        os.mkdir(output_dir)
+
+    msg_path = os.path.join(os.path.dirname(os.path.realpath(__file__)),"..")
+    msg_files = get_msgs_list(msg_path)
+    msg_files.sort()
+
+    filelist_in_markdown=''
+
+    for msg_file in msg_files:
+        msg_name = os.path.splitext(msg_file)[0]
+        output_file = os.path.join(output_dir, msg_name+'.md')
+        msg_filename = os.path.join(msg_path, msg_file)
+        print("{:} -> {:}".format(msg_filename, output_file))
+
+        #Format msg url
+        msg_url="[source file](https://github.com/PX4/PX4-Autopilot/blob/main/msg/%s)" % msg_file
+
+        msg_description = ""
+        summary_description = ""
+
+        #Get msg description (first non-empty comment line from top of msg)
+        with open(msg_filename, 'r') as lineparser:
+            line = lineparser.readline()
+            while line.startswith('#') or (line.strip() == ''):
+                print('DEBUG: line: %s' % line)
+                line=line[1:].strip()+'\n'
+                stripped_line=line.strip()
+                if msg_description and not summary_description and stripped_line=='':
+                    summary_description = msg_description.strip()
+
+                msg_description+=line
+                line = lineparser.readline()
+            msg_description=msg_description.strip()
+            if not summary_description and msg_description:
+                summary_description = msg_description
+            print('msg_description: Z%sZ' % msg_description)
+            print('summary_description: Z%sZ' % summary_description)
+            summary_description
+        msg_contents = ""
+        #Get msg contents (read the file)
+        with open(msg_filename, 'r') as source_file:
+            msg_contents = source_file.read()
+
+        #Format markdown using msg name, comment, url, contents.
+        markdown_output="""# %s (UORB message)
+
+%s
+
+%s
+
+```c
+%s
+```
+""" % (msg_name, msg_description, msg_url, msg_contents)
+
+        with open(output_file, 'w') as content_file:
+            content_file.write(markdown_output)
+
+        readme_markdown_file_link='- [%s](%s.md)' % (msg_name,msg_name)
+        if summary_description:
+            readme_markdown_file_link+=" — %s" % summary_description
+        filelist_in_markdown+=readme_markdown_file_link+"\n"
+
+    # Write out the README.md file
+    readme_text="""# uORB Message Reference
+
+:::note
+This list is [auto-generated](https://github.com/PX4/PX4-Autopilot/blob/main/Tools/msg/generate_msg_docs.py) from the source code.
+:::
+
+This topic lists the UORB messages available in PX4 (some of which may be may be shared by the [PX4-ROS 2 Bridge](../ros/ros2_comm.md)).
+Graphs showing how these are used [can be found here](../middleware/uorb_graph.md).
+
+%s
+    """ % (filelist_in_markdown)
+    readme_file = os.path.join(output_dir, 'README.md')
+    with open(readme_file, 'w') as content_file:
+            content_file.write(readme_text)