chore: deprecate Kubernetes 1.17 support

[jackfrancis]

Reason for Change:

This PR removes support for building new 1.17+ clusters using AKS Engine. The final 1.17 release (1.17.17) was released on Jan 13, 2021:

• https://github.com/kubernetes/kubernetes/releases/tag/v1.17.17

Kubernetes v1.17.17 was added to AKS Engine starting with version v0.60. We recommend that folks who require new 1.17 clusters going forward to continue to use v0.65.0 to do so.

Issue Fixed:

Credit Where Due:

Does this change contain code from or inspired by another project?

• No
• Yes

If "Yes," did you notify that project's maintainers and provide attribution?

• No
• Yes

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[jackfrancis]

cc @jadarsie this PR removes 1.17 support for Azure Stack as well. The proposal here is that the next Azure Stack Hub release of aks-engine will include updated version support requirements stating that 1.18 is the minimum supported Kubernetes version.

WDYT?

[jadarsie]

cc @jadarsie this PR removes 1.17 support for Azure Stack as well. The proposal here is that the next Azure Stack Hub release of aks-engine will include updated version support requirements stating that 1.18 is the minimum supported Kubernetes version.

WDYT?

It is OK on our side, we are recommending v1.18 or higher as well

[jadarsie]

These can also go away

https://github.com/Azure/aks-engine/blob/master/vhd/packer/install-dependencies.sh#L238-L239
https://github.com/Azure/aks-engine/blob/master/vhd/packer/configure-windows-vhd.ps1#L118

[Michael-Sinz]

Good overall - just to minor comments.

[jackfrancis]

thx for the feedback @jadarsie and @Michael-Sinz, this is ready for final review

[jadarsie]

Sorry, one more

https://github.com/Azure/aks-engine/pull/4553/files#diff-ecea196b3e53529d7b6dda4b18339f6c0fc0e83cde6d418b30949dcb2219d751L122

[jackfrancis]

Sorry, one more

https://github.com/Azure/aks-engine/pull/4553/files#diff-ecea196b3e53529d7b6dda4b18339f6c0fc0e83cde6d418b30949dcb2219d751L122

Not sure what this means

[jadarsie]

Sorry, one more
https://github.com/Azure/aks-engine/pull/4553/files#diff-ecea196b3e53529d7b6dda4b18339f6c0fc0e83cde6d418b30949dcb2219d751L122

Not sure what this means

aks-engine/vhd/packer/configure-windows-vhd.ps1

Line 121 in 14beec4

"https://kubernetesartifacts.azureedge.net/kubernetes/v1.17.17/windowszip/v1.17.17-1int.zip",