O4a online dtdphi plotter

This patch allows the following dtdphi plot to be uploaded to gracedb page.
Example G-event pages:
MDC 3-ifo event (two dtdphi plots)
MDC 2-ifo event (one dtdphi plot)
MDC 1-ifo event (no dtdphi plot)

TODO:

• test with single triggers
• test with online small analysis
• try adding LV plot and see if that is informative any way

gstlal-inspiral/python/plots/Makefile.am

@@ -3,6 +3,7 @@ plotsdir = $(pkgpythondir)/plots
 
 plots_PYTHON = \
 	bank.py \
+	dtdphi.py \
 	far.py \
 	horizon.py \
 	lloid.py \