Add a possibility to define a binary mirror

[mfahlandt]

Description of the feature you would like to add / User story

As a user
I would like to replace the default base site for binaries
in order to make a fully offline k1 installation

Solution details

Add a new Option to the KubeOne config file to define a core URL for all binaries

Each of the binaries that are installed are then being pulled from this baseURL, the subpath stays the same

Alternative approaches

Include all the binaries in a bigger installer, but this would be too big potentially to satisfy all optional binaries available

Use cases

It is currently not possible to do a 100% offline and Airgapped installation as the binaries are being pulled out of GitHub

[mfahlandt]

/assign

[xmudrii]

/retitle Add a possibility to define a binary mirror