Well-known warg path

[lann]

RFC 8615 specifies a pattern for HTTP-based service discovery in the form of "well known" paths like /.well-known/<service name>.

Warg API services can use this mechanism to a) help clients positively identify a domain as being a Warg host and b) provide endpoint configuration.

Akin to RFC 8555's "Directory object" we can specify that a domain hosting a Warg service must serve https://<domain>/.well-known/warg/endpoints.json with a JSON document containing a set of endpoint URLs. The set of endpoints would be TBD but for example:

GET https://registry.example.com/.well-known/warg/endpoints.json

{
  // Transparency services with base URL `https://registry.example.com/warg/v1/transparency/...`
  "transparency": "/warg/v1/transparency",
  // Content services with base URL `https://warg-content.example.com/v1/...`
  "content": "https://warg-content.example.com/v1"
}