Update X logo, add Mastodon and Linkedin in social media share

Hello, following this Slack thread: https://eclipsefoundation.slack.com/archives/C1DJQ3ZTR/p1713521864667309 I'm creating this issue for tracking reason.

When creating a Staff Blog post, I have realized that X logo need to be updated and it will be ideal to add Mastodon and LinkedIn, @cguindon is working on it.

Thank you!