Add Float16Schema

[reczkok]

This PR adds support for Float16 schema. Since the support for DataView float16 functions and Float16Array is very limited it does not rely on them. Instead, it provides two functions numberToFloat16 and float16ToNumber that are simple conversion functions based on the IEEE 754 format (essentially binary64 -> binary16).

What it does:

• Adds a Float16Schema that supports reading/writing binary16 floats
• Adds utility functions that convert binary64 (number) to binary16 (float16)
• Adds tests for Float16Schema I/O

What it lacks:

• Support for f16Array

[iwoplaza]

Thanks for the contribution! Just have one note, other than that, amazing work 🌟

[iwoplaza]

Awesome job! 🌟 💛