add `unix2datetime(...; localtime)` functionality (#50296)
Closes: #49297
I feel this implementation works well. I have also created a
`LOCALEPOCH` variable so that a local functionality can be provided to
other functions as well if required. Let me know if this is a good way,
or the implementation must be different, or maybe creating a
`unix2datetime(x::Real; local::Bool=false)` function to kind of merge
both.
Also, I am bit confused about how I would write tests for this.
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Co-authored-by: Steven G. Johnson <stevenj@mit.edu>
Co-authored-by: Max Horn <max@quendi.de>
Co-authored-by: Steven G. Johnson <stevenj@alum.mit.edu>
Co-authored-by: Curtis Vogt <curtis.vogt@gmail.com>
