Update time zone database from Olson database

I'm working on a project that has been using your erlang_localtime library to do conversions between UTC and local times for other places, and I noticed a bit of code such as the following to remap the timezone argument to the library calls.

```
remap_tz ("America/Los_Angeles") -> "America/Los Angeles";
remap_tz ("Asia/Tel_Aviv") -> "Asia/Jerusalem";
```

It was clear to me that our arbitrary set of mappings was likely nowhere near complete. When I looked at the code for your library I couldn't tell what the source of your timezone data was, but it didn't appear to be the [Olson timezone database](https://www.iana.org/time-zones) that most Unix systems use, so I suggested to my manager that I write a converter from the Olson database to the format that the erlang_localtime library uses. This pull request is the result of that work.