Allow Pecan to use 'debuginfo' response field

Currently we have Pecan app improperly integrated with WSME, api
config does not include 'wsme' section. Therefore 'debuginfo'
response field intended to carry exception traceback when server
in debug mode is never used. This patch adds wsme section to api
config with debug field picked from ironic.conf.
This patch also adds documentation references for existing configs.

Change-Id: Iabc042a533c0e3357853a01267ea2252bd61e6e1
Closes-Bug: #1254002
Apply comments to 58558/4 post-landing

review.openstack.org/#/c/58558/4 was accidentally approved with
2 remaining comments. Apply these comments in this patch.

Change-Id: I42fc5784210cb6c9d91db1911b10c21dd31fc0cf
Merge "Apply comments to 58558/4 post-landing"
Merge "Allow Pecan to use 'debuginfo' response field"