Add initialLocations in Research page in order to filter the initial posts

[orestisathanasopoulos]

resolve #825

Add initialLocations in Research page in order to filter the posts shown by default

This solution filters the initial posts by initialising the filteredLocations state with the const InitialLocations in order to use the same filters as the home page.

I only used the function extractCountryIdFromPathname used in the useCountryId hook to extract the country id and not the entire hook since it's not possible to call a hook inside another hook.

For the U.S. the filtered locations include the general United States tag and all individual states tags since all state related posts also include the general tag.

(On a slightly unrelated note, I'm not the most experienced developer and I haven't been contributing to open source for a very long time, so please feel free to let me know if my PRs are not following best practices or to provide feedback on my code if necessary)

[MaxGhenis]

Thank you @orestisathanasopoulos! I've requested others with more knowledge of the codebase to review this. Really appreciate it.

We have a couple other PRs that should help get past the CI issues more automatically, though for now could you run prettier to format the code?

[orestisathanasopoulos]

Thanks @MaxGhenis! I ran prettier which seems to have fixed the issue in Research.jsx but has also created a conflict in the markdown file that I didn't modify

[nikhilwoodruff]

Thanks @orestisathanasopoulos! Tested locally and works exactly as expected.

[nikhilwoodruff]

(also fixed the merge conflict)