Governance Guidance

Guidance on governance topics for the service manual. Content has been
created by the Governance guidance team. Content edited by Beck
Thompson. Have reviewed service manual inclusion with James Abley and
Anjum Shabbir.
It seems that 'focused' (single 'l') is our [preferred version](https://github.com/alphagov/government-service-design-manual/search?utf8=%E2%9C%93&q=focused) of that word, even though both are gramatically correct in this context. Would you mind changing it?