Add MLFlow run name option in config

[awhazell]

Description

Adds an mlflow_run_name option to the config. Currently exclusive with the wandb name, however this matches current functionality where the run_name is set to None if wandb is not in use

#1959

Motivation and Context

We are using axolotl with mlflow to do many fine tuning runs on varying datasets and parameters, it would be nice to be able to tag them when generating the configs rather than having to query the parameters. e.g. 'dataset-a-learning-rate-2e-5'

How has this been tested?

• Running an unchanged config to check no breakages
• Running a new config with an additional mlflow_run_name parameter in the config and checking that the run name is set as desired

Screenshots (if appropriate)

Types of changes

Social Handles (Optional)