Format repository with purs-tidy

[andys8]

With the goal of consistent formatting and import order across examples the repository is formatted with purs-tidy, a dependency and the configuration are added to the repository. Asked upfront if a change like this makes sense and am open to apply changes to .tidyrc.json if they're prefered.

Changes

• Initial repository formatting (make format)
• make formatCheck command is added and executed on CI