DO-1984: Reduce cost of node-pr workflow

[TheOrangePuff]

Description of the proposed changes

This PR aims to make our node-pr workflow cheaper to run on average.Previously we had split workflows into many jobs to make them run faster and be easier to digest and debug. However due to GitHub rounding up build minutes on jobs, this turned out to be quite expensive when multiple jobs would only run for 10 seconds or so.

Therefore, I've combined testing, linting and formatting checks into one job. I've also removed the cleanup step and replaced it with a simple expiry after one day. This might cause issues in large repos so we'll have to see how it behaves. If it does, I can look back into using native caches (although this caused weird permission issues).

I've also split some of the shared logic into composite actions. I can see these potentially being useful across other workflows too so I think it makes sense to do this.

Toggl: DO-1984: Code review

Notes to reviewers

ℹ️ When you've finished leaving feedback, please add a final comment to the PR tagging the author, letting them know that you have finished leaving feedback

[TheOrangePuff]

I think this might actually break things... Not sure if the composite actions will work. Testing now

[TheOrangePuff]

Alright that works now: https://github.com/aligent/aligent-aws-access-cdk/actions/runs/21417701677/job/61670907112
You need to reference the workflow directly rather than with relative paths.