T6832: VyOS v1.4+ chronyd conf support (#357)
- VyOS v1.4+ chronyd conf support
- template typo fix
- Making replace tool more robust by distinctive placeholder
- allow-clients workaround
- test for ntp_global and v1.4
- sanity and change log
- sanity fix
- updates to tests (dynamic >.pool) and docs
- doc update 'system' > 'service'