Improve iOS bindings

[bitsandfoxes]

We're generating bindings for our Cocoa SDK via https://github.com/getsentry/sentry-dotnet/blob/main/scripts/generate-cocoa-bindings.ps1 which has turned laborious and brittle.

Issues

• Not reentrant
• Trouble handling Swift headers
• Very hard to extend

[jamescrosswell]

@bitsandfoxes did you have any alternative solutions in mind? It seems like we have to use objective sharpie... and like some post generation cleanup is necessary (since it doesn't always get it right). What were you thinking we might be able to improve?

[bitsandfoxes]

Most ideas floating around were coming from @brustolin.
One of those was to create the bindings manually for all the API that the SDK actually uses. Ideally, this would be maintained by the Cocoa team.
The way I see it we get to either invest into automation that seems to keep breaking and needs to be maintained or we invest into creating a stable bridge that needs to be maintained to keep up to date with the evolving Cocoa SDK.

[brustolin]

or we invest into creating a stable bridge that needs to be maintained to keep up to date with the evolving Cocoa SDK.

Keep in mind that we dont release public API very often.

[jamescrosswell]

@aritchie suggested we could use Slim Bindings for this. Maybe we do this in the future if there's a major bump to the Cocoa SDK which is difficult to handle via Objective Sharpie