[Europython2020-sprint] Remove old CLI

[louisguitton]

Description

While going through the documentation (at this stage) I was intrigued by the fact that the kedro CLI uses the iris starter as the default starter, and wanted to check if that was set as default in the click command.
So I opened kedro/cli/cli.py only to realise that it was the old version of the CLI and that the starter argument was not there at all.
I went to setup.py and confirmed L177 that the new CLI is used:

entry_points={"console_scripts": ["kedro = kedro.framework.cli:main"]}

Therefore, I'm removing the old CLI.

Development notes

Checklist

• Read the contributing guidelines
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change and added my name to the list of supporting contributions in the RELEASE.md file
• Added tests to cover my changes

Notice

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• I certify that the use of this contribution as authorised by the Apache 2.0 license does not violate the intellectual property rights of anyone else.

[mzjp2]

Deleting the old CLI is a breaking change, so this would need to be merged into develop instead, since master contains backwards-compatible code to be released in 0.16.x and develop contains all breaking changes which will be merged in for 0.17.

I believe develop has already deleted the cli code so there isn’t anything to do :)