Add function timeout support

[pmuens]

Add function timeout support for all the different providers.

The timeout config will be provided with the help of the function config file. There should be a default timeout and it should be possible to rewrite this through provider-related middlewares.

[vincentsolutions]

Hey @pmuens , is there any kind of update about this?

This would be a great addition for event-gateway users until it's ready for production!

Based on my initial investigation, it seems like every request has a set timeout of 2 or 3 seconds.

Maybe there's a quick fix we can currently use until there's a more solid solution in the future? For example just by hard-changing the default timeout value?