Parameterize tasks to support both CFF and Tanzu stacks

[TisVictress]

Some of the tasks in this public CI can be used in the buildpacks private CI. These tasks should be refactored to make it more usable and avoid code duplication. For instance, the make-rootfs, generate-rootfs-receipt-diff, run-rootfs-smoke-test and get-cf-creds tasks have been copied to the to the private CI to change how the inputs are used in the tasks.

Similarly, create-rootfs-bosh-release-github-release-notes should be updated so that any pipeline using this task has more control over the release notes. Right now, the tanzu-cflinuxfs3-release notes points to a broken link.