Add a high-level mission statement to the requirements doc?

[austinpray]

https://github.com/UTD-CRSS/project.exploreapollo.org/blob/4cdf979010d73996d7d605c1cc05c62ed0628862/requirements/v1.md

We should add probably add some sort of mission statement or project statement here to give an overview of what we are trying to accomplish.