chore: add docs for layer selection

[Racer159]

Description

Adds some documentation for UDS Layer Selection and Pre-req packages.

Related Issue

Fixes #N/A

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide followed

[UnicornChance]

1. Can you upload the drawio file as well to the diagrams folder for future updates?
2. @mjnagel if we want to keep some consistency with the other diagrams that we just reworked, probably should update the color scheme. Also fine doing this myself once the drawio file is uploaded.

[mjnagel]

@UnicornChance yeah agreed - we should try and keep color schemes aligned going forward.

@Racer159 maybe broader question on the diagram - is there a reason it needs to even be a diagram? I don't have a strong objection, but given that it's essentially a colored table (no diagram elements where layout/flow need to be consider) then would we be better served just making it in markdown?

[Racer159]

@UnicornChance yeah agreed - we should try and keep color schemes aligned going forward.

@Racer159 maybe broader question on the diagram - is there a reason it needs to even be a diagram? I don't have a strong objection, but given that it's essentially a colored table (no diagram elements where layout/flow need to be consider) then would we be better served just making it in markdown?

I can definitely make it a table - it just started as a diagram initially since I thought it might be more - I'll go ahead and massage it into a table