v1.21.0

• Feature: Remove usage of host ssh keys when building
• Feature: Added edge-core support for network proxy
• Rename snaap-var edge-proxy.extern-http-proxy
• Switch all repo URIs to https
• Bug fix: Update edge-node-modules to fix build breakage
• Bug fix: Don't immediately re-register after factory reset
• Bug fix: Kubectl fails to start after factory reset
• Bug fix: Permission denied when cleaning go modules
• Bug fix: Delete top-level snap vars on factory reset
• Bug fix: Layout feature does not require passthrough plug
• Bug fix: restart-delay feature does not require passthrough plug
• Bug fix: Build warning about empty LD_LIBRARY_PATH