Revert old guessers and tables removal (#4752)

* Add back MDAnalysis.topology's guessers and tables modules
* Adds deprecation warnings for these two modules

---------

Co-authored-by: Oliver Beckstein <orbeckst@gmail.com>

package/CHANGELOG

@@ -114,6 +114,10 @@ Changes
    numpy.testing.assert_allclose #4438)
 
 Deprecations
+ * MDAnalysis.topology.guessers is deprecated in favour of the new
+   Guessers API and will be removed in version 3.0 (PR #4752)
+ * MDAnalysis.topology.tables is deprecated in favour of
+   MDAnalysis.guesser.tables and will be removed in version 3.0 (PR #4752)
  * Element guessing in the ITPParser is deprecated and will be removed in version 3.0
    (Issue #4698)
  * Unknown masses are set to 0.0 for current version, this will be depracated