Replace `call_external`'s implementation with an async one

[techmetx11]

The original call_external is kept as call_external_sync

Fixes #1759

[jubalh]

I don't quite see where call_external_sync() is used/needed now?

[techmetx11]

Me neither, I left it there for compatibility, but maybe it'll be better if I remove it

[jubalh]

We are no library :) So don't need to worry about compatibility in the regard of not renaming/removing functions.

I'll have to check the code later. Did you test if all the situations that use this function now still work?

[techmetx11]

We are no library :) So don't need to worry about compatibility in the regard of not renaming/removing functions.

I'll have to check the code later. Did you test if all the situations that use this function now still work?

I've only tested it with /url open right now

[techmetx11]

If all the functions that use call_external work you can actually remove call_external_sync, no need to keep it.

I removed it now :3

[jubalh]

Did you also test the functionality which calls this function?

And since it's now two commits about one change you can squash it into one.

[techmetx11]

Did you also test the functionality which calls this function?

And since it's now two commits about one change you can squash it into one.

I've tried it out with /avatar open, /url open (both HTTP and AESGCM) and /url save I'll squash it

[jubalh]

Thanks for your contribution @techmetx11 !