Fix page layouts template page

[SeamusLeonardHPE]

The existing page layouts figma templates file has a number of issues that make it less than ideal for a product to designer to copy & paste as a starting point.

• The page templates use a mix of frames, groups and shapes that are hard to interact with and add content to.
• The our figma grid styles do not comply to the recommended margins in the page guidance.
• There are on page guidance layers that re not locked.
• Page widths seem

These page templates should be modified to make them easier to comprehend & copy/paste & populate with content.

• [x] Fix and standardise page layout (frames, alignment, global header, auto-layout?)
• [x] Decide if needed guidance overlay is needed per page, if so how to lock it.
• [x] Investigate, and recommend a better way to incorporate/enforce guidance with figma layout grids.
• [x] Decide if these modified templates should be moved into the template library
• [x] If existing page template file is to be left in place, all WIP & exploration pages should be archived elsewhere.
• [x] If guidance is to remain on page, update, reformat & tidy to new specs
• [ ] Check guidance site for links & copy that may need updated.