1123 population data for different years

[patricklnz]

Changes and Information

Please briefly list the changes (main added features, changed items, or corrected bugs) made:

-Population Data can now be downloaded for past years, specified with ref_year -The test for total population has been adjusted to be 5% accurate to 8.4 million

If need be, add additional information and what the reviewer should look out for in particular:

-

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• [x] Tests are added for new functionality and a local test run was successful (with and without OpenMP)
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Checks by code reviewer(s)

• [x] Corresponding issue(s) is/are linked and addressed
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• [x] Appropriate unit tests have been added, CI passes, code coverage and performance is acceptable (did not decrease)
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closes #1123

[mknaranja]

The incorrect population data makes our ESID scenario pipeline failing and this should be repaired soon.

@patricklnz Are you still adding some unit tests as Henrik requested? That'd be great! Could you also provide some information on what you did in the issue? @HenrZu Did you do a full review? Could you otherwise please do soon?