added export to restic vars

[cryptozero]

restic can't access env vars and cron fails

[g7eg10r]

Hi guys, just facing the opposite issue: on a Debian 8, cron (version 3.0pl1-127+deb8u1) complains about "bad minute" lines within the generated crontab because of the exports and refuses to load it.
It works perfectly (environment variables are propagated to restic) when the export part is removed.
Can you provide more background about why you did that change? Thanks.

[g7eg10r]

@cryptozero, just saw your commit reverting this change in your repo (cryptozero@452cd79). What about adding a configuration variable that would be used in the template to indicate if environment variables should be exported or not?