Make headers case sensitive

[fractalf]

Looks like custom headers are forefully sent as lower case...
Which is not such a good idea?

[kofta999]

This is probably a limitation from reqwest (the underlying library that ATAC uses to send requests) per the documentation

[Julien-cpsn]

If you find any way to disable it at runtime, I'll create a variable in the app config file like case_insensitive_headers = true/false

[kofta999]

Sure I'll take a look at it, so far I found this method in reqwest but doesn't seem to be working, and this discussion where the author gave up and made its own implementation.
So I guess it's either replacing reqwest (probably tedious to do) or we create a fork that has this option