Forecasting sdk and environment changes

[simmonsj330]

Description

Updating conda-3-9-env-full.yml to use u8darts instead of u8darts[torch] because they point to the same conda-forge source (this fixes #3348). Additionally, fixing dependency version issues which were identified when creating a new environment with forecasting and installing the sdk. Lastly, updating the SDK_README.md to demonstrate the proper way to create an environment if the user would like to utilize forecasting features.

Working forecasting menu installed by created an environment with conda create -n <environment> -c conda-forge python=3.9.6 u8darts=0.22.0 pytorch-lightning=1.6.5 -y

Only one pre-commit issue was flagged but it is acceptable because it is related to an example secret in SDK_README.md

Others

• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.

[jmaslek]

@martinb-bb/ @Lukazcreations is this good?

[martinb-ai]

@simmonsj330 ^^ please check the update i just made to the reqs.txt to make sure that protobuf version doesn't break anything