FAST: fixes to GitHub workflow and 02/net outputs

[ludoo]

This fixes a few things in the GitHub workflow

• include plan stderr in PR comment
• remove the code to post to the action status page, as that too has a message length limit
• additional step to error workflow if plan or apply fails, needed since the plan and apply steps have continue-on-error: true to allow the PR comment step to always run
• set continue-on-error: true on the step that posts the PR comment, and add a second step that posts a shorter comment which omits plan standard output in case of failure due to comment length

It also fixes file outputs for the networking stages, which raise an error if the outputs_location variable is not set.