Deprecate periodic effects classes and remove associated tutorial (#738)

Author: dylanhmorris

docs/tutorials/.pages

@@ -6,4 +6,3 @@ nav:
   - latent_hierarchical_infections.md
   - right_truncation.md
   - day_of_week_effects.md
-  - periodic_effects.md

docs/tutorials/periodic_effects.qmd

@@ -6,12 +6,7 @@
     IIDRandomSequence,
     StandardNormalSequence,
 )
-from pyrenew.process.periodiceffect import DayOfWeekEffect, PeriodicEffect
 from pyrenew.process.randomwalk import RandomWalk, StandardNormalRandomWalk
-from pyrenew.process.rtperiodicdiffar import (
-    RtPeriodicDiffARProcess,
-    RtWeeklyDiffARProcess,
-)
 
 __all__ = [
     "IIDRandomSequence",
@@ -20,8 +15,4 @@
     "DifferencedProcess",
     "RandomWalk",
     "StandardNormalRandomWalk",
-    "PeriodicEffect",
-    "DayOfWeekEffect",
-    "RtPeriodicDiffARProcess",
-    "RtWeeklyDiffARProcess",
 ]