Add x-api-key header to avoid rate limiting

[markmhendrickson]

See relevant info here from @zone117x

[fbwoolf]

Note, the linked repo is private. The key and endpoint are to remain private during testing.

[zone117x]

Hey guys, any update on this?

[markmhendrickson]

It looks like we kicked off work on the web wallet for this (leather-io/extension#2446) but not the desktop one.

@fbwoolf is your immediate sense that the desktop wallet change here be a small or big lift in light of knowing how to do it for the web wallet already?

[fbwoolf]

The work here is mostly in updating all the libraries needed and if those updates will cause errors that need to be fixed. I am not as familiar with the desktop code, but the work in the wallet was fairly minimal. However, I still haven't heard back on how testing has gone with the wallet build.

[zone117x]

@fbwoolf the changes made in the web wallet seem to be working well so far, I left a comment in that PR.