feat: NLog support

[bruno-garcia]

Docs to NLog integration brought in by @josh-degraw
@josh-degraw Could you please also review it?

[bruno-garcia]

Package still beta so build isn't happy about it since it can't find it in the registry.
I'll publish it next week so once the PR is approved I can merge it right after releasing it.

[josh-degraw]

Looks good to me, just a few comments / requests that I thought of.

[josh-degraw]

One thing that might be good to super clarify is that as of now, it doesn't use the standard NLog way of specifying the log level.

For example, you typically you set the minlevel on the rule for the lowest rule you want to be logged, but here there are the MinimumEventLevel and MinimumBreadcrumbLevel in addition to the standard. I think it's pretty straight forward and it is explained in these docs, but it might be good to draw attention to this difference here, e.g.:

<!--
      NOTE: If the `minlevel` for the logger is higher than `MinimumBreadcrumbLevel`, those messages 
      won't be added as breadcrumbs.

      Set the minlevel as low as possible to allow all messages to 
      pass through sentry target, and configure levels for breadcrumbs and events above.
-->
<logger name="*" writeTo="sentry" />
<!-- The above is equivalent to <logger name="*" minlevel="Trace" writeTo="sentry"/> -->

It could be worded however, but I think it would be good to make sure that is super duper clear so people can make sure their breadcrumbs are sent to sentry correctly.

[bruno-garcia]

I've added a note about this. I tried to be detailed on how it works but still seems confusing. Would appreciate some suggestions.
Or feel free to make a PR on this branch too if you wish :)

[josh-degraw]

One thing I just thought of is that I specified that the Dsn is specified as a required parameter in the SentryTarget, which means that if a sentry target is defined in the NLog.config file without a dsn specified, it will probably not register the target correctly.

I'd have to test it to verify that, but that could cause issues if people want to set the dsn another way. So that should either be documented here or else changed on the target, which I'm happy to do if you think that's the better option.

[bruno-garcia]

Right. We should make this not required then. Firstly because the lack of DSN means don't initialize Sentry at all but also because It's important to make it possible for integration not to initialize the SDK. The canonical way to init any Sentry SDK from the unified API is via Sentry.Init so allowing an integration initialize the SDK is just a convenience for those who use a single integration. It also helps making things idiomatic.

Could you please modify the integration to make DSN optional?

[josh-degraw]

Can do. I should be able to send a PR this weekend.

[MimiDumpling]

Just a couple grammar things. :) Thanks for all your work!