update universal build tool article to reflect decision to use colcon (#168)

* update universal build tool article to reflect decision to use colcon

* fix spelling / missing word

* add next steps, implications, outlook

* fix spelling

* rephrase

* wording

* spelling

* Wjwwood/build tool colcon (#169)

* typo

* clarify how the decision was made

* add a few more items to the list of things needed to complete the colcon option

* clarify future plans for ROS 1

* typo

* note existing case for catkin packages and devel space versus install rules

* remove line about devel space

* remove cross compilation

* minor tweaks

* add progress section to link to relevant PRs

* fixups

* update archival time for ament_tools

* mention inferring metadata

* keep abstract sentence

* punctuation for readability

Author: dirk-thomas