Remove (Out-of-Date) Mission from HQ (and instead just link to start-here)

[nelsonic]

At present the @dwyl mission statement is in multiple places and the one in HQ: https://github.com/dwyl/hq#mission-statement is out of sync with the recently updated https://github.com/dwyl/start-here/pull/191 >> /start-here/mission.md

I propose that we:

• [x] remove the mission statement from HQ (unless you feel it's relevant as an "intro" to the topic of "dwyl's operations and administration"...) and instead we add it to the start-here#why (which in turn would link to /start-here/mission.md for more detail)

.then HQ can simply

• [x] link to start-here for the people who don't know what @dwyl is.

[nelsonic]

PR: #548

[nelsonic]

GOTO: /mission.md