Run preinstall.sh and postinstall when upgrading via apk

[sean-breen]

Proposed changes

In Alpine Linux, the preinstall and postinstall scripts will not be executed during an upgrade scenario. This adds the missing scripts to be executed during the apk upgrade which will handle config migration if coming from an agent version less than 3.*.

Also removes the postupgrade.sh script, as the agent restart is being handled by the postinstall.sh

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• I have run make install-tools and have attached any dependency changes to this pull request
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• If applicable, I have updated any relevant documentation (README.md)
• If applicable, I have tested my cross-platform changes on Ubuntu 22, Redhat 8, SUSE 15 and FreeBSD 13

[dhurley]

You need to update the .nfpm.yaml file in the root directory as well.