doc: add pw-v4l2.1 and spa-*.1

Add manpages for the remaining utilities without one.

doc/dox/programs/pw-v4l2.1.md

@@ -0,0 +1,40 @@
+\page page_man_pw-v4l2_1 pw-v4l2
+
+Use PipeWire instead of V4L2
+
+# SYNOPSIS
+
+**pw-v4l2** \[*options*\] *COMMAND* \[*ARGUMENTS...*\]
+
+# DESCRIPTION
+
+**pw-v4l2** runs a command using a compatibility layer that maps PipeWire
+video devices to be visible to applications using V4L2.
+
+This is implemented by preloading a shared library via LD_PRELOAD,
+which translates library calls that try to access V4L2 devices.
+
+# OPTIONS
+
+\par -h
+Show help.
+
+\par -r NAME
+The name of the remote instance to connect to. If left unspecified, a
+connection is made to the default PipeWire instance.
+
+\par -v
+Verbose operation.
+
+# EXAMPLES
+
+**pw-v4l2** v4l2-ctl --list-devices
+
+# AUTHORS
+
+The PipeWire Developers <$(PACKAGE_BUGREPORT)>;
+PipeWire is available from <$(PACKAGE_URL)>
+
+# SEE ALSO
+
+\ref page_man_pipewire_1 "pipewire(1)",