[Documentation] Support of Machine-to-Machine (M2M) token

[RamanDamayeu]

We need to update the documentation according to the changes made in #1646 to facilitate machine-to-machine (M2M) (a. k. a. system-to-system (S2S)) communication raised in #1639.

There is a blog post to be used for reference https://blog.opendatadiscovery.org/odd-update-support-for-machine-to-machine-m2m-tokens-c1e2bf71c566

[RamanDamayeu]

Documentation has been updated:

1. Features: https://docs.opendatadiscovery.org/features#machine-to-machine-m2m-tokens
2. ODD Platform configuration: https://docs.opendatadiscovery.org/configuration-and-deployment/odd-platform#machine-to-machine-m2m-tokens-configuration