Deprecate lal.spectrum python module
This merge adds a DeprecationWarning to lal.spectrum - this module hasn't been maintained properly in ages, and isn't really used by anyone, so we may as well remove it; people should use gwpy instead.
Maintenance will be performed on git.ligo.org, containers.ligo.org, and docs.ligo.org on Tuesday 23 April 2024 starting at approximately 9am PDT. It is expected to take around twenty minutes and there will be several periods of downtime throughout the maintenance. Please address any comments, concerns, or questions to the helpdesk.
This merge adds a DeprecationWarning to lal.spectrum - this module hasn't been maintained properly in ages, and isn't really used by anyone, so we may as well remove it; people should use gwpy instead.