Admin guide have unclear swift-recon output details

[Gui Maluf Balzana]

On #cluster-telemetry-and-monitoring section description of recon API is pretty unclear.

swift-recon and its API outputs many meaningful values which are not pretty explained on docs.

* include the difference between `swift-recon` and `curl /recon` output
* include reference links for terms like quarantined, updater, async, audit. What is async pending? which kind of task generates async pending? what unit its been use for those values? what it really mean?
* /load: also returns quantity of processes and tasks
* /devices: returns directory list in devices dir, something like `ls -d /srv/node/*`

Would be nice if those values were better explained for monitoring purpose.