Decide what to do with /system/indy-sdk-tests tests

[WadeBarnes]

system/indy-sdk-tests rely on the deprecated indy-sdk, these tests should be migrated to use indy-vdr, or deprecated and removed.

[swcurran]

Do you have an opinion @WadeBarnes ? Presumably there is an example of how to change tests from one to the other. Do you know of any example? I did see in the payments tests removal PR that some of those were using indy VDR.

[WadeBarnes]

My opinion is the we should keep and migrate tests that appear to have value. Which those are, I don't know, because I haven't looked that deeply into it.

May of the tests were migrated from using the indy-sdk to indy-vdr already, that history can be used as the reference.