Consistently refer to plans by consistent names

[illicitonion]

CodeYourFuture/Module-Structuring-and-Testing-Data#9 refers to a Build Your Life plan and a Career Development plan.

The previous courseworks (CodeYourFuture/Module-User-Focused-Data#59, CodeYourFuture/Module-User-Focused-Data#51, CodeYourFuture/Module-User-Focused-Data#53, CodeYourFuture/Module-User-Focused-Data#49) refer to these with different names.

We should pick consistent names for these plans, and refer to them thus, rather than using lots of different terms to refer to them. I wasn't sure, on first read, whether "Build Your Life Plan" was referring to the "Life as a developer" plan or the "Development plan".

/cc @kfklein15