feat: adding support to dynamic external path load

[michelreipsporter]

#5718

[fabiankoebel]

Thanks for the updates and the effort you've put into this PR.

Could you please upmerge the latest main branch again and resolve the remaining conflicts? Once that's done, is there a way to request integration into main, or is there any additional process we should follow?

Thanks!

[michelreipsporter]

Thanks for the review.

I've already upmerged the latest main branch and resolved all remaining conflicts. The branch is now up to date with main and should be ready for integration.

Regarding the integration, the implementation included in this PR should be enough. To use it, it is only necessary to configure the external endpoint and enable the feature through:

pathExternalConfEnabled: true
pathExternalConfURL: http://your-server/api/streams

Once those settings are configured, MediaMTX will fetch path configurations from the external endpoint and the integration should work as expected.

Please let me know if there's any additional process required before merging.
Thanks!