TypeScript 3.0.0 Upgrade

[agubler]

Enhancement

Upgrade typescript version to 3.0.0

[agubler]

Closing this for now, there is forwards compatible support from 2.6.1 to 3.2.x which means that the frameworks TS version does not restrict the version of TS for a user.

We'll create another issue when we are preparing to upgrade the minimum supported TS version for the framework, with the reasoning and benefits associated.