Remove the EXPEDITE_DEPLOYMENT variable automatically

What does this MR do?

• In case of emergency situations can be stressful situations, let's remove this variable to ensure that we don't accidentally forget about it in the future
• We create a job dedicated to this task that runs only if the variable is set
  • Other rules are put into place to prevent other mistakes
• Documentation created to reflect this automation

Addresses: gitlab-com/gl-infra/delivery#1902 (closed)

Author Check-list

Please read the Contributing document and once you do, complete the following:

• Assign to the correct reviewer per the contributing document
• Apply the correct metadata per the contributing document
• [-] Link to related MRs for applying the changes on other environments
• [-] Link to related Chef changes
• [-] If necessary link to a Criticality 4 Change Request issue

Reviewer Check-list

• Reviewed the diff jobs to confirm changes are as expected
• No changes shown in the diffs not associated with this MR - This may require a rebase or further investigation