### Body

The CLI:

`airflow variables set [-h] [-j] [-v] key VALUE`

https://airflow.apache.org/docs/apache-airflow/stable/cli-and-env-variables-ref.html#set_repeat1

Doesn't support adding description though column exists and we support it from Rest API:
https://airflow.apache.org/docs/apache-airflow/stable/stable-rest-api-ref.html#operation/post_variables

**The Task:**

Allow to set description from cli command

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
ARG_ACCESS_LOGFILE = Arg(
    ("-A", "--access-logfile"),
    default=conf.get("webserver", "ACCESS_LOGFILE"),
    help="The logfile to store the webserver access log. Use '-' to print to stdout",
)
ARG_ERROR_LOGFILE = Arg(
    ("-E", "--error-logfile"),
    default=conf.get("webserver", "ERROR_LOGFILE"),
    help="The logfile to store the webserver error log. Use '-' to print to stderr",
)
ARG_ACCESS_LOGFORMAT = Arg(
    ("-L", "--access-logformat"),
    default=conf.get("webserver", "ACCESS_LOGFORMAT"),
    help="The access log format for gunicorn logs",
)
ARG_INTERNAL_API_PORT = Arg(
    ("-p", "--port"),
    default=9080,
    type=int,
    help="The port on which to run the server",
)
ARG_INTERNAL_API_WORKERS = Arg(
    ("-w", "--workers"),
    default=4,
    type=int,
    help="Number of workers to run the Internal API-on",
)
ARG_INTERNAL_API_WORKERCLASS = Arg(
    ("-k", "--workerclass"),
    default="sync",