Add isolated diego cells for devtools

[cweibel]

Changes proposed in this pull request:

• This change supports adding a devtools isolation segment to dev/stage/prod and mapping this to their "production" cf org.
• Leverages automation to generate iso segs based on upstream and our customizations laid out in https://github.com/cloud-gov/internal-docs/blob/f258ec118fc5a0d6401eca86a6d8d0242ad69925/docs/runbooks/Platform/adding-isolation-segments.md but also automate mapping the org to the iso seg.
• Part of https://github.com/cloud-gov/private/issues/2472

security considerations

Secrets stored in credhub, just adding a single iso segment to dev/stage/prod