core.usermanager: Add scoped luacheck ignore rule to reduce clutter

mod_authz_internal: Expose convenience method to test if user can assume role

mod_authz_internal, and more: New iteration of role API These changes to the API (hopefully the last) introduce a cleaner separation between the user's primary (default) role, and their secondary (optional) roles. To keep the code sane and reduce complexity, a data migration is needed for people using stored roles in 0.12. This can be performed with prosodyctl mod_authz_internal migrate <host>

util.roles: Add Teal interface declaration

mod_admin_shell: Show session role in c2s:show

usermanager: Add back temporary is_admin to warn about deprecated API usage Goal: Introduce role-auth with minimal disruption is_admin() is unsafe in a system with per-session permissions, so it has been deprecated. Roll-out approach: 1) First, log a warning when is_admin() is used. It should continue to function normally, backed by the new role API. Nothing is really using per-session authz yet, so there is minimal security concern. The 'strict_deprecate_is_admin' global setting can be set to 'true' to force a hard failure of is_admin() attempts (it will log an error and always return false). 2) In some time (at least 1 week), but possibly longer depending on the number of affected deployments: switch 'strict_deprecate_is_admin' to 'true' by default. It can still be disabled for systems that need it. 3) Further in the future, before the next release, the option will be removed and is_admin() will be permanently disabled.

usermanager: Remove concept of global authz provider Rationale: - Removes a bunch of code! - We don't have many cases where an actor is not bound to one of our hosts - A notable exception is the admin shell, but if we ever attempt to lock those sessions down, there is a load of other work that also has to be done. And it's not clear if we would need a global authz provider for that anyway. - Removes an extra edge case from the necessary mental model for operators - Sessions that aren't bound to a host generally are anonymous or have an alternative auth model (such as by IP addres). - With the encapsulation now provided by util.roles, ad-hoc "detached roles" can still be created anyway by code that needs them.

usermanager: Fix method name of global authz provider (thanks Zash)

usermanager: Remove obsolete function from global authz provider

features: Add "permissions" feature for role-auth