Decouple from legacy ydb

Remove kikimr/go/ydb dependency, this one is used only for wierd things, so instead of depended on whole legacy driver just make a copy of required interfaces.

Copy-paste of decimal parser would be removed once this: <ydb-platform/ydb-go-sdk#1436> is released.
2850b0e5f684b6bc933c812440f687cc9245836d

go.mod

@@ -31,7 +31,6 @@ require (
 	github.com/goccy/go-json v0.10.3
 	github.com/godror/godror v0.29.0
 	github.com/gofrs/uuid v4.2.0+incompatible
-	github.com/golang-jwt/jwt/v4 v4.5.0
 	github.com/golang/mock v1.7.0-rc.1
 	github.com/golang/protobuf v1.5.4
 	github.com/golang/snappy v0.0.4
@@ -150,6 +149,7 @@ require (
 	github.com/go-ole/go-ole v1.2.7-0.20211215081658-ee6c8cce8e87 // indirect
 	github.com/godror/knownpb v0.1.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang-jwt/jwt/v4 v4.5.0 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/google/flatbuffers v23.5.26+incompatible // indirect
 	github.com/google/s2a-go v0.1.7 // indirect