Deprecate the 'jf rt atc' command

[yahavi]

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The /artifactory/api/security/token endpoint is deprecated in Artifactory.
Deprecate jf rt atc and suggest using jf atc instead. jf atc is using the /access/api/v1/tokens API.

./jf rt atc
10:54:27 [🟠Warn] You are using a deprecated syntax of the command.
	Instead of:
	$ jf rt atc ...
	Use:
	$ jf atc ...

Downside - The jf atc does not support basic auth:

./jf atc
10:55:03 [🚨Error] authenticating with access token is currently mandatory for creating access tokens

[StephenWithPH]

@yahavi I'm seeing other bad behavior regarding auth (similar to your comment above) with jf atc now that it has replaced jf rt atc. For example, #2490 .