docs: create documentation for simulator module

docs/source/simulator/index.rst

+Simulator
+=========
+
+This module hosts functionality for running simulators, as well as some
+simulators used in the landslide community.
+
+Currently implemented classes are:
+
+* :class:`.RunSimulator`:
+
+* :class:`.MassPointModel`:
+
+* :class:`.Ravaflow24Mixture`:
+
+.. toctree::
+   :maxdepth: 1
+   :hidden:
+   :caption: Simulator
+
+    Run Simulator <run_simulator>
+    Mass Point Model <mass_point_model>
+    Ravaflow Mixture Model <ravaflow24>
\ No newline at end of file

docs/source/simulator/mass_point_model.rst

+Mass Point Model
+----------------
+
+MassPointModel Class
+^^^^^^^^^^^^^^^^^^^^
+
+The :class:`.MassPointModel` class is imported by::
+    
+    from psimpy.simulator.mass_point_model import MassPointModel
+
+Methods
+*******
+.. autoclass:: psimpy.simulator.mass_point_model.MassPointModel
+    :members: run
\ No newline at end of file

docs/source/simulator/ravaflow24.rst

+Ravaflow24 Mixture Model
+------------------------
+
+Ravaflow24Mixture Class
+^^^^^^^^^^^^^^^^^^^^^^^
+
+The :class:`.Ravaflow24Mixture` class is imported by::
+    
+    from psimpy.simulator.ravaflow24 import Ravaflow24Mixture
+
+Methods
+*******
+.. autoclass:: psimpy.simulator.ravaflow24.Ravaflow24Mixture
+    :members: preprocess, run, extract_impact_area, extract_qoi_max, extract_qoi_max_loc
\ No newline at end of file

docs/source/simulator/run_simulator.rst

+Run Simulator
+-------------
+
+RunSimulator Class
+^^^^^^^^^^^^^^^^^^
+
+The :class:`.RunSimulator` class is imported by::
+    
+    from psimpy.simulator.run_simulator import RunSimulator
+
+Methods
+*******
+.. autoclass:: psimpy.simulator.run_simulator.RunSimulator
+    :members: serial_run, parallel_run
\ No newline at end of file