TS-3033: generic message initial marshalling

Implement a very simple generic message marshalling API. This is
similar to the existing hand-rolled marshalling, except that there
are fewer data types, and it is all implemented in a single place.

Add MgmtSocket.cc because there's really no benefit to having all
the mgmt socket wrappers inline. Move some more helper API over to
MgmtSocket.
TS-3033: reimplement management API with generic marshalling

This reimplements the management protocol on top of the generic
message marshalling API.
TS-3034: add unanchored regex option

Add unanchored regex option and use it for traffic_line -m so that
filtering record names is easier.
TS-3041: traffic_layout tool

Add a simple traffic_layout tool to show the location of various
installation paths and resources.
TS-3042: fix the static traffic_server build

Rename --enable-static-libts to --enable-static-proxy, since that's
a better description of what it does. Use this option to default
the libtool static library options so that it works correctly.