Fix egress proxy route bug

[rahearn]

🎫 Addresses issue: no issue

🛠 Summary of changes

• validates that the default route name for the egress proxy starts with a letter
• adds the optional ability to manually specify what the route hostname should be
• updates some obsolete README content from the v2 transition

[pauldoomgov]

I wish apps.internal was scoped to the org level, but alas... I think squishing and keeping the last 63 chars is the least bad option, and thanks for the test! LGTM!