Authenticate and create/retrieve Activity records (incidents, near misses, audits) via the Cority Enviance EMS REST API

Steps

1. Note that use of the API requires an express Cority Enviance Connectors license from Enviance/Cority; the Swagger spec at `https://api.enviance.com/Swagger.svc/swagger.json` is publicly viewable, but calls will fail authentication without a contracted license.
2. Obtain a session with `POST /ver2/AuthenticationService.svc/sessions`, sending a JSON body `{"userName": "...", "password": "..."}`; the response returns a SessionId.
3. Send that SessionId on every subsequent call as `Authorization: Enviance <SessionId>` (an OAuth-token flow is also available via `POST /ver2/AuthenticationService.svc/oauthtoken` using a refresh token).
4. Create an Activity (e.g., a near-miss or incident record) with `POST /ver2/ActivityService.svc/activities`, supplying `name`, `templateIdOrName`, and a `fields` array of `{name, values}` pairs matching the target template's configured fields.
5. Retrieve, update, or delete a specific activity with `GET`/`PUT`/`DELETE /ver2/ActivityService.svc/activities/{activityIdOrName}`, addressing it by its ID or unique name.
6. Call `DELETE /ver2/AuthenticationService.svc/currentsession` to explicitly end the session when finished.