Unify the way k0s binary is installed after upload or download

[kke]

Signed-off-by: Kimmo Lehto [email protected]

Before this PR the k0s binary was installed to the K0sBinaryPath in three different ways depending on:

• If the file was uploaded from local k0s binary cache to the host
• If the file was downloaded directly to the host from the k0s repository
• If performing an upgrade to a running k0s instance (and also this would branch depending on the two ways to get the binary to the host above)

With this PR, the final binary installation is done using the same function.

This may help with the selinux issue in #440 or at least provides a single place where the selinux permission granting can be done.