Namespaces are too tightly bound to app URLs

[jace]

Client app resource namespaces (see #90) are currently required to match the website URL's base domain (from #117). For eg, if the client app's website is https://funnel.hasgeek.com/, the namespace is required to begin with com.hasgeek. as hasgeek.com is the base domain.

If the client app moves to a different website, like https://funnel.hasgeek.com/ becoming https://talkfunnel.com/, the namespace is also required to change from com.hasgeek.funnel to com.talkfunnel (without trailing periods).

This breaks other client apps that request access to resources since the namespace is meant to be an unchanging unique identifier. To address this, we have to:

1. Allow client apps to keep their old namespace. Since any future edits will have to be validated, this will mean keeping a historical list of namespaces. Or,
2. Keep a historical list of namespaces (without exclusivity) but enforce #117 (as present) and transparently redirect resource requests to the new namespace on the basis of the most recent app to have used the old namespace (only currently active namespaces are exclusive to the app).