jsctl config: handle nested keys

[abom]

We need to handle nested keys with jcstl config, maybe dot-separated

For example, we cannot set the value of the hostname of the redis store directly:

[stores]

[stores.redis]
hostname = "localhost"
port = 6379

It would be better to do it like e.g. poetry config:

jsctl config get stores.redis.hostname

jsctl config update stores.redis.hostname 172.17.0.2

What needed to be done:

• [x] support nesed keys in get/set of core.config module
• [x] prohibit updating non-existent keys
• [x] parse the value arguement using toml decoder and fallback to string when an error occurs
• [x] ensure type compatibility between old value and updated value
• [x] change the following name/value options to arguments

@config.command()
@click.option("--name")
def get(name):
    value = get_config()[name]
    click.echo(format_config_parameter(name, value))

@config.command()
@click.option("--name")
@click.option("--value")
def set....

[abom]

still needs verification

[alichaddad]

Verifying