Reduce use of 'The competition' as the SR year

Replace with various uses of the "build period"
Fix ommited word
Change location to web, rather than a physical loc
Team leaders also enforce our rules locally

(i.e., MCFS)
Bitbox no longer sponsor us
Drop bitbox, remunge footer
Centering
Rulebook documents kit to return, not all kit
The webiste has the full list of kit.
Tighten can't-keep-the-kit wording
Leave MCF / Ticket definition til later
We announce two things, so define them.
Don't use undefined 'event page'
Feedback suggests softening of teacher-help claim

Specifically, directing their design might be telling them that they
can't build a robot out of cheese, so let the teacher give advice.
Strengthen claim about team-leaders responsibility
Strengthen tool-supervision claim
Team leaders are responsible for collecting kit
Competitors should never use teacher accounts
Reduce bottom page margin
Link to user management documentation