Refactor wire schema format (#121)

Resolves #52
Resolves #87
Resolves #119

- Refactored wire schema format to reduce its size.
  The size went from 184 bytes to 16 bytes for Otel/STEF Metrics.
  See specification.md for the description of the new format.
  This is important if in the future we decide to add a stateless
  network protocol where the size of the schema on the wire is
  important since it is repeated for every payload.

- Added new randomized tests that verify writing/reading STEF streams
  with overridden schema (narrowed schema than generated) to
  ensure the new wire schema format works correctly.

- The new tests found several bugs in codecs that needed to be fixed.

There is no measurable change in performance, verified by
running the benchmarks.

Author: tigrannajaryan