feat: added custom settings section

[zvikarp]

This PR allows users to add custom settings to the talker settings page.

These custom settings are not managed or stored by talker but are just displayed on the settings page. The settings can be grouped into groups and each group can be enabled or disabled. I understand if you decide not to merge this because it is a bit out of scope for collecting logs, but it is super helpful for me, as I prefer to have just one place to all debug related things, I'm using it in multiple apps and thought I'll share it.

Thank you for developing and maintaining this great package :)