Improve the flow for setting/changing/resetting User password to make
it more secure.
1. Modify `User.resetPassword` to create a token scoped to allow
invocation of a single remote method: `User.setPassword`.
2. Scope the method `User.setPassword` so that regular tokens created
by `User.login` are not allowed to execute it.
For backwards compatibility, this new mode (flow) is enabled only
when User model setting `restrictResetPasswordTokenScope` is set to
`true`.
3. Changing the password via `User.prototype.patchAttributes`
(and similar DAO methods) is no longer allowed. Applications
must call `User.changePassword` and ask the user to provide
the current (old) password.
For backwards compatibility, this new mode (flow) is enabled only
when User model setting `rejectPasswordChangesViaPatchOrReplace` is set
to `true`.
Fix the code builing a scoped method to correctly handle the case
when the setup method is called twice and the previously defined
method has to be overriden with new remoting metadata.
Define a new property `AccessToken.scopes` to contain the list of
scopes granted to this access token.
Define a new remote method metadata `accessScopes` to contain a list
of scope name required by this method.
Define a special built-in scope name "DEFAULT" that's used when
a method/token does not provide any scopes. This allows access
tokens to grant access to both the default scope and any additional
custom scopes at the same time.
Modify the authorization algorithm to ensure that at least one
of the scopes required by a remote method is allowed by the scopes
granted to the requesting access token.
The "DEFAULT" scope preserve backwards compatibility because existing
remote methods with no `accessScopes` can be accessed by (existing)
access tokens with no `scopes` defined.
Impact on existing applications:
- Database schema must be updated after upgrading the loopback version
- If the application was already using a custom `AccessToken.scopes`
property with a type different from an array, then the relevant code
must be updated to work with the new type "array of strings".
Miroslav Bajtoš