net/chrony: Update to 3.3

• Add explicit DOCS, EXAMPLES options
• Replace %%PREFIX%% in sample files
• Make sure chronyc is really linked with libedit from ports
• Add support for security/nettle and use it by default since chrony crashes on startup when built with NSS. [1]

PR: 227779, 223840 [1]
Submitted by: takefu@airport.fm
Approved by: maintainer