Exchangeratesapi.io was bought and now requires a key

Found another alternative not listed here, and added it: Exchangerate.host

* Add SpaceTradersAPI

-[x] My submission is formatted according to the guidelines in the contributing guide
-[x] My addition is ordered alphabetically
-[x] My submission has a useful description
-[x] The description does not end with punctuation
-[x] Each table column is padded with one space on either side
-[x] I have searched the repository for any relevant issues or pull requests
-[x] Any category I am creating has the minimum requirement of 3 items
-[x] All changes have been squashed into a single commit

I removed the required lines

Note: The PR #1085 is inative.

Resolve #1085

As reported in #1660

Update README.md

Update README.md

Remove duplicate weatherstack entry.

 Only leave it in the Weather section.

Squash commits.

Note:
    The user deleted the fork from this project, so it will not be possible to resolve the conflict for the merger.

Close #1281

Removed inactive Linkedin API

As per requested @marekdano

As requested by the reviewer PR updated in order to fix API duplication and missing https for hubblesite.