doc(contribute): update & fix team page - socials & images

[erisu]

Motivation and Context

Fix Team Page

Description

• Replaced Twitter Icon with X
• Replaced imageurl data with github username.
• Added GitHub links
• Updated everyone's image with file name matching GitHub username. (Using external resources is blocked on ASF)

Testing

n/a

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary