chore: move open-api docs to open openapi.yaml OR openapi.json

[rackstar]

The openapi docs is currently inline and its a little bit hard to read the routes file and know what exactly are the routes available because the openpi docs is so big.

For readability move it to its own file rather than inline.

TODO: point to openapi.yaml / json

 apis: [path.resolve(__dirname, '../routes/*.js')], // files containing annotations as above

https://github.com/NexusMutual/cover-router/blob/master/src/lib/swagger.js