Migration: Refactored the way network connections are modeled per issue 126

[Jamie-SA]

Tasks for migration - write queries to do the following:

• networkConnection renamed to links
• hasFromNode renamed to linksFrom
• hasToNode renamed to linksTo
• Verify/warn if new restriction (on NetworkLink that it must have exactly 2 links) fails
• Verify/warn if new restrictions (on NetworkLink and NetworkNode that they must be memberOf a Network) fail

[uscholdm]

@Jamie-SA @rjyounes Can this be closed now?

[rjyounes]

Out-of-date.