**Description**

Enabled list of cors headers origin allowed

**Use case / motivation**

I'm currently developping Django application working with apache airflow for some external work through api. From Django, user run dag and a js request wait for dag end. By this way, I enabled cors headers in airflow.cfg with correct url. But now, I've  environment (dev & prod). It could be useful to be able to set more than one url in airflow.cfg cors header origin allowed

Thank's in advance :) 

airflow/configuration.py
"""Historical getboolean"""
    warnings.warn(
        "Accessing configuration method 'getboolean' directly from the configuration module is "
        "deprecated. Please access the configuration from the 'configuration.conf' object via "
        "'conf.getboolean'",
        DeprecationWarning,
        stacklevel=2,
    )
    return conf.getboolean(*args, **kwargs)
def getfloat(*args, **kwargs):
    """Historical getfloat"""
    warnings.warn(
        "Accessing configuration method 'getfloat' directly from the configuration module is "
        "deprecated. Please access the configuration from the 'configuration.conf' object via "
        "'conf.getfloat'",
        DeprecationWarning,
        stacklevel=2,
    )
    return conf.getfloat(*args, **kwargs)
def getint(*args, **kwargs):
    """Historical getint"""
    warnings.warn(
        "Accessing configuration method 'getint' directly from the configuration module is "
        "deprecated. Please access the configuration from the 'configuration.conf' object via "
        "'conf.getint'",
        DeprecationWarning,
        stacklevel=2,
    )
    return conf.getint(*args, **kwargs)
def getsection(*args, **kwargs):