Create generic "Offline First" presentation

[gr2m]

I think one thing that we could do for the community is to prepare a generic "Offline First" presentation that is hosted on GitHub, that others can use as a starting point for giving talks on Offline First in their respective communities.

@bradley-holt offered to provide content

[mmcelaney]

@bradley-holt can we use your presentation for this?

[bradley-holt]

@mmcelaney Happy to have any of my material reused for this purpose. Not sure the best format to share it in. I create my presentations in PowerPoint (because reasons).