Make URL structure more consistent with the information architecture

## What Align the paths and URLs of pages to their categorisation from the ['Tutorials and guides' page](https://prototype-kit.service.gov.uk/tutorials-and-guides/), setting up the appropriate redirections for people who may have bookmarked them. ## Why The URLs of most pages, and their path in the filesystem, does not reflect their categorisation from the ['Tutorials and guides' page](https://prototype-kit.service.gov.uk/tutorials-and-guides/). It'd help maintenance to align the URLs and paths, and open the door to computing breadcrumbs more automatically. ## Who needs to work on this Developers, with support from Content designers ## Who needs to review this Developers, with support from Content designers ## Done when - [ ] File paths and URLs of pages align with their categorisation on Tutorials and guides - [ ] Redirects have been set up for the existing URLs