There's currently an `sop.adoc` page which looks like a bad wiki
conversion of a list of links to the miscellaneous SOPs. We
already have `index.adoc` as a *working* list of links to the
miscellaneous SOPs, so this is pretty redundant, let's just drop
it. Also dropped: sop_update_releng_docs , which is entirely
outdated.
Also, make `index.adoc` and the nav sidebar link to the sigul
client setup SOP which they're currently missing, and update the
SOP template page a bit.
Signed-off-by: Adam Williamson <awilliam@redhat.com>
