Make references to crow less obvious

Recently, a number of people in the community have made the (admittedly
easy) mistake that we use a significant portion of crow.

Today, we use crow for the router, and the "app" structure, and even
those have been significantly modified to meet the bmc needs.  All other
components have been replaced with Boost beast.  This commit removes the
crow mentions from the Readme, and moves the crow folder to "http" to
camouflage it a little.  No code content has changed.

Tested:
Code compiles.  No functional change made to any executable code.

Signed-off-by: Ed Tanous <ed.tanous@intel.com>
Change-Id: Iceb57b26306cc8bdcfc77f3874246338864fd118