(PDB-221) Add facts to import/export

This commit imports/exports facts similar to how we currently import/export
catalogs and reports. Anonymize doesn't currently work for facts, which is
going to be added separately.
Merge pull request #874 from kbarber/ticket/master/PDB-470-setStatementsCacheSize

PDB-470 Provide new db setting 'statements-cache-size' with a default of...
Aded Archlinux build/install support
Merge pull request #876 from aboe76/master

Aded Archlinux build/install support
Added support for exporting facts/reports when
no catalog has been persisted for the given node
Merge pull request #875 from senior/ticket/master/pdb-221

(PDB-221) Add facts to import/export
PDB-473 Support POST using application/json data in the body

This patch adds to the commands end-point the ability to simply POST using
application/json with the JSON content in the body.

It also switches the terminus to use this mechanism.

We found that the url encode/decode required to support x-www-form-urlencoded
was actually quite an overhead in a number of ways:

* The urlencode on the terminus added overhead
* The urldecode in the server added overhead
* The interim strings created during this encode/decode process can get quite
  large increasing the amount of garbage collection required

This has been done by providing a new middleware that will move the body into
the param "payload" when the content-type is set to application/json. This
provides a convenient backwards compatible layer so that the old form url
encoding can still be supported.

Signed-off-by: Ken Barber <ken@bob.sh>