Add disk buffering config options to RUM conf

[mhennoch]

Currently iOS and android have different config options for enabling and configuring disk buffering.

Android enableDiskBuffering limitDiskUsageMegabytes

iOS enableDiskCache spanDiskCacheMaxSize

Also react native needs to use the same conf. After discussions it seems "buffering" makes more sense so let's use android version. Not sure where to put mobile only conf options put them into the same table.

[github-actions[bot]]

CLA Assistant Lite bot All contributors have signed the CLA ✍️ ✅

[mhennoch]

I have read the CLA Document and I hereby sign the CLA

[Kielek]

@signalfx/gdi-ios-maintainers, FYI