Rt cmd migration

[fluxxBot]

• All tests have passed. If this feature is not already covered by the tests, new tests have been added.
• The pull request is targeting the dev branch.
• The code has been validated to compile successfully by running go vet ./....
• The code has been formatted properly using go fmt ./....

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depends on :-

1. Rt cmd migration jfrog-cli-artifactory#58
2. Rt cmd migration jfrog-cli-core#1370

[RobiNino]

Haven't went over all of it yet, a few questions / suggestions by now:

1. Why wasn't artifactory/cli.go moved as a whole? That way we wouldn't need to handle merging a namespace (appendNewCommands).
2. Please delete in this PR everything that was moved (docs, utils, flags, etc) to avoid duplications.

[fluxxBot]

Haven't went over all of it yet, a few questions / suggestions by now:

1. Why wasn't artifactory/cli.go moved as a whole? That way we wouldn't need to handle merging a namespace (appendNewCommands).
2. Please delete in this PR everything that was moved (docs, utils, flags, etc) to avoid duplications.

@RobiNino This was done to avoid moving build commands, since build commands are depended on jfrog-cli-security and as we know jfrog-cli-security is already using jfrog-cli-artifactory, we do not want to introduce a cyclic dependency here.