Remove /stand-alone from console install dir.

[ErnieAllen]

This patch removes the last part of the console install directory: /stand-alone.
In addition, the httpRoot config file entry for a listener is now optional. The router will attempt to serve the console from the new install dir.

To disable serving the console on an http enabled listener, set the httpRoot attribute to 'None'.

This PR also updated the readme files for the console and the httpRoot attribute description in the schema.

[codecov-io]

Codecov Report

Merging #475 into master will increase coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #475      +/-   ##
==========================================
+ Coverage   86.69%   86.72%   +0.03%     
==========================================
  Files          86       86              
  Lines       19086    19085       -1     
==========================================
+ Hits        16546    16552       +6     
+ Misses       2540     2533       -7

Impacted Files	Coverage Δ
src/connection_manager.c	89.48% <100%> (+0.16%)	⬆️
...re/modules/edge_addr_tracking/edge_addr_tracking.c	83.87% <0%> (-1.08%)	⬇️
src/router_core/route_tables.c	76.67% <0%> (-0.25%)	⬇️
src/router_node.c	94.19% <0%> (ø)	⬆️
src/router_core/router_core.c	87.09% <0%> (+0.21%)	⬆️
src/remote_sasl.c	83.88% <0%> (+1.11%)	⬆️
...c/router_core/modules/test_hooks/core_test_hooks.c	93.94% <0%> (+1.27%)	⬆️

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[grs]

Looks good to me!