feature: Provide mechanism for duplicating tokens across windmill instances

[ChrisEdgington]

I want to run multiple exact-copy windmill deployments for two purposes:

Load-balance between them to mitigate platform / region connectivity and downtime
Blue-green deployment of new windmill versions

The only limiting issue I have discovered is that I need to be able to share the same webhook tokens between instances. I thought I could just move auth to the load balancer and have the load balance inject the instance-specific token - but then I lose the ability to do token-label based filtering in the dashboard.

This could be as simple as allowing me to specify the token value when creating tokens via the API. Then I could create a token on one instance and use that value to create the same token on another instance.