CNG: Set timezone environment variable

Summary

Providing the TZ environment variable, either directly, or via an export in the wrapper scripts, would significantly reduce the number of times that Rails reads /etc/localtime, resulting in faster rendering and response times.

We should consider performing this in all containers. Ruby, Go, et al.

See related issues.

Current behavior

TZ environment variable is not set

Expected behavior

TZ environment variable to be set

Versions

• Chart: 2.5.x / master

Relevant links

• gitlab-org/omnibus-gitlab#3530 (closed)
• gitlab-org/gitaly#143 (closed)
• https://twitter.com/yukihiro_matz/status/1201347711984787458?s=19
• https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html

Thanks @brodock for calling this out as a difference between Omnibus GitLab and the CNG.