Rewrite settings implementation: Use predefined static configurations

[inakianduaga]

Instead of passing the settings per request (too much overhead, too unconventional for documenting/implementing), we do the following

• Optionally provide a json file with configuration groups by keys (so angular-project1 : ... would be a set of configuration that we can access through angular-project1 key, etc). These definitions live on the server and must be hardcoded into the application (NOT the repo)
• The post route for logging has a parameter that will accept a configuration key string. If it's empty or it doesn't match a configuration, the default configuration will be used, otherwise we will extend the default configuration with the preconfigured key one.
• Same for the get method to retrieve an effective configuration.

This is much better since it's very simple to implement on the client side (no extra parameters on the client side), has no overhead on the log requests, and basically makes sense since the server will usually take logging from a small set of applications that can be preconfigured instead of some random request that would need really dynamic configuration

[inakianduaga]

TODO

On services/settings.ts we need to replace the old requestHeaderSettingsField parameter by the group id and build the config using that

[inakianduaga]

Multiple winston loggers

Use https://github.com/winstonjs/winston#working-with-multiple-loggers-in-winston