Set a default storageAdapter

[kingo55]

We originally stripped this from the library because we thought the storageAdapter was too opinionated and in order to conserve weight.

However I think in the interest of making setup easier, we should consider providing a default one out of the box (either through our shared code or hardcoded into the library):

https://github.com/mint-metrics/mojito-js-delivery/blob/master/lib/mojito.js#L106-L110

[kingo55]

Notes

Add this into the shared-code.js section where users can easily override.

Can have this commented out by default so it doesn't add to the weight.

[kingo55]

Done - Closing.