[Types] Add proper types for "Schema.index"

[hasezoey]

Do you want to request a feature or report a bug?
types

What is the current behavior?
for function (new Schema()).index definition everything is any, at least option should be assigned to IndexOptions

and IndexOptions should extend / use from mongodb's IndexOptions

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
mongoose 5.13.5

[Raader]

#10538