Add heroku scaling commands to publication process

[JPrevost]

Why are these changes being introduced:

• the preservation job uses a lot of memory. Scaling the worker job where preservation is done to a dyno with additional memory will help give us a bit more headroom

Relevant ticket(s):

• https://mitlibraries.atlassian.net/browse/ETD-598

How does this address that need:

• provides instructions on how and why to scale the worker dyno before and after processing the output queue for publishing jobs

Document any side effects to this change:

• This doesn't really solve the problem, but masks it for our common thesis sizes. To fully address this problem we'll need to revisit how we create the preservation zip files

Developer

• All new ENV is documented in README
• All new ENV has been added to Heroku Pipeline, Staging and Prod
• ANDI or Wave has been run in accordance to
  our guide and
  all issues introduced by these changes have been resolved or opened as new
  issues (link to those issues in the Pull Request details above)
• Stakeholder approval has been confirmed (or is not needed)

Code Reviewer

• The commit message is clear and follows our guidelines
  (not just this pull request message)
• There are appropriate tests covering any new functionality
• The documentation has been updated or is unnecessary
• The changes have been verified
• New dependencies are appropriate or there were no changes

Requires database migrations?

NO

Includes new or updated dependencies?

NO

[coveralls]

coverage: 98.313%. remained the same
when pulling c041bcd on etd-598-publishing-memory-spikes
into 81d1964 on main.

[matt-bernhardt]

This seems pretty straightforward and easy to follow.