ENH: Add access for Australian astronomical data

[bsipocz]

I'm opening this issue here, so users and contributors of astroquery who may not follow the wider astropy project roadmap can see about the plans of adding AAO data access.
(I got a question recently about SkyMapper, and while encouraged them to open an issue and discussion, it highlighted that we haven't made any reference issue about the plans here in astroquery).

See more info: AAO Research Data & Software

cc @NuriaLorente

[jenosoko]

@bsipocz thanks for opening this issue. I am the person leading the team that is keen to get access to SkyMapper data in astroquery. What are the steps I should take to speed this process along? Thanks!