First draft completed disability_daily_activities

[CatReid]

First draft completed disability_daily_activities, styled and rendered. data.R and metadata updated.

Fixed errors in data.R for air-pollution

[jennajt]

Refactored R script:

• In general it is better to use the lookup tables rather than the population dataset when you are creating a lookup for ltla name and code as they will be more up to date and it doesn't confuse the script. In this instance I've left it as the population dataset but changed the comments - to make it clear why we are using the population dataset - and renamed the table to lookup rather than population
• Used "pivot wider" and "groupby/summarise" to achieve the required data transformation