List Pools Containing Text

Add ability to list pools containing text in a number of requested fields. (SKU, SKU name, provided product IDs and names, order number, contract number, SLA attribute) This will be exposed in subscription-manager shortly.

Supports * and ? for wildcards.

Discovered we already have a similar mechanism for searching for pool attributes. Combined the two approaches resulting in some improvements for pool attribute searching as well. The pool attribute search is also leveraged internally for checking the SLA.
:+1:  Nice tests.