Since Go 1.22 has deprecated certain elliptic curve operations, this PR removes
references to the affected functions and replaces them with a custom implementation
in package crypto. This causes backwards-incompatible changes in some places.
---------
Co-authored-by: Marius van der Wijden <m.vanderwijden@live.de>
Co-authored-by: Felix Lange <fjl@twurst.com>