Timber 2.0

[binarylogic]

1. Captures all HTTP server request / response headers and body.
2. Captures controller calls params.
3. Capture user context earlier in the stack via warden if it is being used.
4. Restructures probes into integrations.
5. Firms up integration tests considerably.
6. Automatically configures the rails logger.
7. Checks for LogRage existence and disables it if present.
8. Simplifies various Rails log subscribers and integrations with simple Rack middlewares.
9. Disables log metadata for local and test environments

Closes https://github.com/timberio/timber-ruby-private/issues/7
Closes https://github.com/timberio/timber-ruby-private/issues/9
Closes https://github.com/timberio/timber-ruby-private/issues/10