the www release package is not portable

in the explorer, a file called endpoints.json describes endpoints used for collecting explorer-related info. this allows it to be easily copied to another internet site and hosted for a different node.

in this repo, a file /poolconfig.json at or /pool/poolconfig.json should describe the pool. then, pool operator can download the latest www from release page and edit poolconfig.json (or keep their old one)

• api path prefix (eg: /api/ or /api/pool/ or https://example.org/api/)
• endpoint: the "Mine To" URL (eg: 1234 or http://example.org:1234 which is equal to http://example.org:1234/{address}/{name})
• pool fee setting (1.5 = 1.5%)
• pool difficulty setting (eg: 3000000)
• name (optional, otherwise use domain name)

something like

{
  "api": "/api/pool/",
  "endpoint": "http://example.org:1234",
  "fee": 1.5,
  "difficulty": 3000000
}

then the frontend can read this poolconfig and display accurate info based on the site it is installed at.

the frontend builder should be able to change this config location, but leaving it at the default place allows others to view it too (for example explorers can display more information about the pool without guessing).

pools that dont use the www from this repo should also be able to host a poolconfig.json file to allow explorers to gather information about them easily, making it easy for users to connect and interact with them.