config: generate model code from json schema

Proposing that the first step towards implementing OpenTelemetry Configuration is to
produce the model code from the json schema. I did a quick search for tools available
to do this and came across datamodel-codegen which seems to do what i expected.

Will open following pull requests (in draft) to use this model code, i just want
to keep these as clearly separated as possible to make reviewing them easier.

Signed-off-by: alex boten <223565+codeboten@users.noreply.github.com>

Author: codeboten