Improvements to aggregation support and foundation work for expressing arbitrary constraints within components.

This change adds support for defining arbitrary conditions which can be used to test properties and their values. Conditions can be used within aggregations to define 1) when a referenced managed object needs enabling and 2) when it is enabled. For example, the LDAP connection handler requires that its key manager provider and trust manager provider are enabled when it is enable and when either SSL or StartTLS are enabled.

Conditions are also intended for use within the existing constraint/dependency support. For example, it should be possible to indicate that a property "min" is always less than or equal to a property "max", or that when "use-ssl" is set to true, any required SSL configuration related properties are also defined. This will be implemented in a subsequent change (this change just focuses on the work required to resolve issue 1449).

This change adds support for the following conditions:

* logical "not"
* logical "and"
* logical "or"
* logical "implies"
* contains - determines if a property contains a particular value
* is-present - determines if a property has any values (incl. defaults)

More will be added as required.