Remove localgov_elections_social_post submodule

[stephen-cox]

Part of #159

What does this change?

Removes the localgov_elections_social_post module. This unblocks the upgrade to Drupal 11.

How to test

Everything else still installs okay and there is no mention in the docs on posting to X.

[AWearring]

Installs OK for me on our West Lindsey build that has LGD Elections installed and enabled.
@stephen-cox do we need to inform others that if they have the module installed that they'll need to disable it first?

[tonypaulbarker]

I ran a test upgrade with the social post modules enabled and nothing complained.

In case someone has enabled this, I think we could consider upgrade instructions to uninstall these in advance to remove their config:

localgov_elections_social_post
social_post_twitter
social_post
social_api

Just to report, localgov_elections_social_post.settings seems to persist. Perhaps it should be removed on uninstall, however it would need to be against 1.x, so unlikely anyone would ever get the hook without additional steps. Don't think it's a blocker.

[stephen-cox]

@tonypaulbarker My thinking was that the upgrade from 1.x to 2.x would in include manual instructions to install things as this would most likely be done as part of a D10 to D11 upgrade.

I can certainly add a hook to do this, but I suggest spinning this out into a separate issue.