design for overload of requestStorageAccess

[dontcallmedom]

(follow up to #29)

IIUC, the current proposal is to have an overloaded version of requestStorageAccess that takes a mandatory parameter types.

WebIDL requires to make optional dictionary parameters if they're last and the dictionary doesn't have required members.

Now, as discussed in #29, it can't be made optional otherwise it is no longer distinguishable from the existing requestStorageAccess.

A few (not thought-through) ideas to resolve that situation:

• instead of an overload, replace the existing requestStorageAccess and have the default value be {cookies: true} (if Web compat requires it) - I don't think that replacing Promise<undefined> with Promise<StorageAccessHandle> would create compat issues
• make one of the member of StorageAccessTypes required (but not sure which one would make sense)
• use a different name for the method (e.g. requestStorageAccessHandle) rather than an overloaded one