collateral-proxy: use in set/verify/recover/SDK, use per-getter config instead of global

[charludo]

This is a couple of related things thrown together in this PR. The commits themselves are rather stand-alone.

• the remaining ticket was to make the proxy be used in set/verify/recover, that is done here
• noticed it should also be usable through the SDK, leading to a small refactor
• noticed when using the proxy in set/verify/recover in e2es I had to clean up the proxy setting since it was global, so refactored to use per-getter config. TBH should probably have been like that from the start.
• and finally, use in set/verify/recover in e2es