[FAB-3095] - Add MSP piece to RTD

This CR cleans up the text and formatting of the
MSP doc and adds it to the TOC.
Small edits from Elli incorporated...
[ci-skip]

Change-Id: Ib81622b5e82d8e97f913b46d2d9b93d3169ceddc
Signed-off-by: Nick Gaski <[email protected]>

Author: nickgaski

docs/source/index.rst

@@ -58,6 +58,7 @@ Before diving in, watch how Fabric is `Building a Blockchain for Business <https
    :caption: Operations Guide
 
    best_practices
+   msp
    configtx
    configtxgen
    cc-packaging-and-signing