The Integrations page on Rsyslog integration should be split up

[TibsAtWork]

For speed/simplicity of migration, the page at docs/integrations/rsyslog.rst gives the documentation for all of the rsyslog integrations, except Datadog, for which it has a link to another page.

Ideally, it would instead be a "contents page" with links to one page for each rsyslog endpoint, held in docs/integrations/rsyslog/ (having such a "contents page" plus an adjacent directory is now a common structure within the documentation).

I've marked this as "good first issue" since it is just rearrangement of existing text, but it's definitely reasonable to ask for help/guidance on how to perform such a split.

[lornajane]

@Ugbot Are you going to be working on this? If not, could you unassign so someone else could pick it up?

[Ugbot]

I was not aware that was assigned to me. I've unassigned it and will review other pending assignments