Bundle tzdata in promtail for non-POSIX hosts

[chancez]

Is your feature request related to a problem? Please describe.
I can't set a timezone in my timestamp pipeline configuration, because on Windows/non-POSIX hosts there's no tz database available to go by default.

Describe the solution you'd like
After discussing with @cyriltovena I also learned Go has an option for bundling tzdata. import _ "time/tzdata"

Describe alternatives you've considered

I believe you can provide your own zoneinfo.zip and provide the path to it via setting the ZONEINFO environment variable, according to https://golang.org/pkg/time/#LoadLocation.

[chancez]

Should be fixed by #3332