Better serialization for `Blob` and `File`

[lxsmnsyc]

Currently Blob and File relies on ArrayBuffer serialization, which means it uses the Uint8Array indirectly. This serialization form is accurate, but is probably too large for consideration. Blob accepts Uint8Array, ArrayBuffer, DataView and string, so it's probably ideal if the string format can be utilized instead.

[lxsmnsyc]

To watch out: https://github.com/tc39/proposal-arraybuffer-base64

[MengLinMaker]

Would you recommend converting Uint8Array to base64 and back?

Sending ArrayBuffer from SolidStart.js use server is slow. Not too sure where the bottleneck is.