Lower memory footprint so iOS extension doesn't crash

[philipphofmann]

Description

According to this GH discussion #4713 (comment) @steviec can't run the Sentry Cocoa SDK in a DeviceActivityMonitor extension, because the Cocoa SDK needs to much memory so the extension crashes. The GH discussion provides more context on ideas on how to lower the memory footprint. The main goal is to reduce the memory footprint for the minimal SDK setup without SR, profiling, or tracing. Everybody would benefit from this initiative.

[philprime]

Idea by @philipphofmann: Binary image cache might not be necessary for crashes.

This will require analysis of memory usage before changes can be proposed.