Point LALSuite wheels to solar_system_ephemerides package for ephemeris files

Description

This MR remove the LALPulsar ephemeris files from the LALSuite wheels (PyPI packages). Instead these files are sourced from the solar_system_ephemerides package. People who need these files can run

pip install lalsuite[lalpulsar]

to install them with LALSuite.

API Changes and Justification

Backwards Compatible Changes

• This change does not modify any class/function/struct/type definitions in a public C header file or any Python class/function definitions
• This change adds new classes/functions/structs/types to a public C header file or Python module

Backwards Incompatible Changes

• This change modifies an existing class/function/struct/type definition in a public C header file or Python module
• This change removes an existing class/function/struct/type from a public C header file or Python module

If any of the Backwards Incompatible check boxes are ticked please provide a justification why this change is necessary and why it needs to be done in a backwards incompatible way.

Review Status

cc @matthew-pitkin @david-keitel @adam-mercer

wheel/setup.py.in

@@ -189,6 +189,9 @@ setup(
         'scipy',
     ],
     extras_require={
+        'ephemerides': [
+            'solar_system_ephemerides',
+        ],
         'lalinference': [
             'gwdatafind',
             'gwpy',