GH-41105: [Python][Docs] Update PyArrow installation docs for conda package split (#41135)

Do not merge until some discussion is had about how to time this relative to conda-forge/arrow-cpp-feedstock#1376. Additionally, consider hot-patching this into arrow-site if appropriate.

### What changes are included in this PR?

Updates to the [Python installation docs](https://arrow.apache.org/docs/python/install.html) to reflect the in-progress change splitting PyArrow on conda-forge into three separate packages. Specifically:

1. Add a note in the conda section highlighting that there are three packages and linking to a new section (2) in order to provide more information
2. Add a new section, linked from (1), providing a comparison of each package as a table

### Are these changes tested?

These are just docs changes. I have built them locally and they look fine.

### Are there any user-facing changes?

Just docs.
* GitHub Issue: #41105

Lead-authored-by: Bryce Mecum <petridish@gmail.com>
Co-authored-by: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Signed-off-by: Bryce Mecum <petridish@gmail.com>

Author: amoeba

docs/source/python/flight.rst

@@ -17,6 +17,7 @@
 
 .. currentmodule:: pyarrow.flight
 .. highlight:: python
+.. _flight:
 
 ================
 Arrow Flight RPC

docs/source/python/install.rst

@@ -39,6 +39,13 @@ Install the latest version of PyArrow from
 
     conda install -c conda-forge pyarrow
 
+.. note::
+
+    While the ``pyarrow`` `conda-forge <https://conda-forge.org/>`_ package is
+    the right choice for most users, both a minimal and maximal variant of the
+    package exist, either of which may be better for your use case. See
+    :ref:`python-conda-differences`.
+
 Using Pip
 ---------
 
@@ -93,3 +100,85 @@ a custom path to the database from Python:
 
    >>> import pyarrow as pa
    >>> pa.set_timezone_db_path("custom_path")
+
+
+.. _python-conda-differences:
+
+Differences between conda-forge packages
+----------------------------------------
+
+On `conda-forge <https://conda-forge.org/>`_, PyArrow is published as three
+separate packages, each providing varying levels of functionality. This is in
+contrast to PyPi, where only a single PyArrow package is provided.
+
+The purpose of this split is to minimize the size of the installed package for
+most users (``pyarrow``), provide a smaller, minimal package for specialized use
+cases (``pyarrow-core``), while still providing a complete package for users who
+require it (``pyarrow-all``). What was historically ``pyarrow`` on
+`conda-forge <https://conda-forge.org/>`_ is now ``pyarrow-all``, though most
+users can continue using ``pyarrow``.
+
+The ``pyarrow-core`` package includes the following functionality:
+
+- :ref:`data`
+- :ref:`compute` (i.e., ``pyarrow.compute``)
+- :ref:`io`
+- :ref:`ipc` (i.e., ``pyarrow.ipc``)
+- :ref:`filesystem` (i.e., ``pyarrow.fs``. Note: It's planned to move cloud fileystems (i.e., :ref:`S3<filesystem-s3>`, :ref:`GCS<filesystem-gcs>`, etc) into ``pyarrow`` in a future release though :ref:`filesystem-localfs` will remain in ``pyarrow-core``.)
+- File formats: :ref:`Arrow/Feather<feather>`, :ref:`JSON<json>`, :ref:`CSV<py-csv>`, :ref:`ORC<orc>` (but not Parquet)
+
+The ``pyarrow`` package adds the following:
+
+- Acero (i.e., ``pyarrow.acero``)
+- :ref:`dataset` (i.e., ``pyarrow.dataset``)
+- :ref:`Parquet<parquet>` (i.e., ``pyarrow.parquet``)
+- Substrait (i.e., ``pyarrow.substrait``)
+
+Finally, ``pyarrow-all`` adds:
+
+- :ref:`flight` and Flight SQL (i.e., ``pyarrow.flight``)
+- Gandiva  (i.e., ``pyarrow.gandiva``)
+
+The following table lists the functionality provided by each package and may be
+useful when deciding to use one package over another or when
+:ref:`python-conda-custom-selection`.
+
++------------+---------------------+--------------+---------+-------------+
+| Component  | Package             | pyarrow-core | pyarrow | pyarrow-all |
++------------+---------------------+--------------+---------+-------------+
+| Core       | pyarrow-core        | ✓            | ✓       | ✓           |
++------------+---------------------+--------------+---------+-------------+
+| Parquet    | libparquet          |              | ✓       | ✓           |
++------------+---------------------+--------------+---------+-------------+
+| Dataset    | libarrow-dataset    |              | ✓       | ✓           |
++------------+---------------------+--------------+---------+-------------+
+| Acero      | libarrow-acero      |              | ✓       | ✓           |
++------------+---------------------+--------------+---------+-------------+
+| Substrait  | libarrow-substrait  |              | ✓       | ✓           |
++------------+---------------------+--------------+---------+-------------+
+| Flight     | libarrow-flight     |              |         | ✓           |
++------------+---------------------+--------------+---------+-------------+
+| Flight SQL | libarrow-flight-sql |              |         | ✓           |
++------------+---------------------+--------------+---------+-------------+
+| Gandiva    | libarrow-gandiva    |              |         | ✓           |
++------------+---------------------+--------------+---------+-------------+
+
+.. _python-conda-custom-selection:
+
+Creating A Custom Selection
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If you know which components you need and want to control what's installed, you
+can create a custom selection of packages to include only the extra features you
+need. For example, to install ``pyarrow-core`` and add support for reading and
+writing Parquet, install ``libparquet`` alongside ``pyarrow-core``:
+
+.. code-block:: shell
+
+    conda install -c conda-forge pyarrow-core libparquet
+
+Or if you wish to use ``pyarrow`` but need support for Flight RPC:
+
+.. code-block:: shell
+
+    conda install -c conda-forge pyarrow libarrow-flight