Optimize CI Workflow by reusing content of static build

[Asiderr]

Discussion base on: #614 (comment)

Problem:

Currently, in our GitHub Actions workflow, we build the site files for each job independently. This approach may lead to redundancy and slower build times, especially when dealing with the "static" content.

Proposal:

We could optimize the workflow by building the "static" content once and then reusing it across all jobs. This would potentially reduce build times and overall resource consumption.

Additional Notes:

If the build speed is already satisfactory, we might not need to implement this optimization.
As of now, the entire CI process completes in less than a minute.