Reduce duplicate code between various backend templates

[james-ball-qualcomm]

I just discovered that the Profile (and hence CRD) backend Ruby templates are copy-and-pasted from the cfg_html_doc. In particular, I just copied more from cfg_html_doc/csr_adoc.erb to get all CSR yaml info added to the CSR appendix of a CSR (e.g. field summary, fields). There was quite a bit of template code I copied which will be hard to maintain going forward (especially if added to a Profile too).