Add links to share a job on Twitter / Facebook / whatevers

[ojongerius]

Granted a single job card does not cover that much info, but it does allow people to quickly share them without leaving the site. Now that #80 is done we can link to urls that are somewhat pretty 🎉

Social suspects:

• Facebook
• Twitter
• Linkedin
• Whatsapp

• Add "share" links to popular social media on job card template jobcard.html

[ojongerius]

If you planned working on this, please hold off on it for now. Chatting to some people about potentially merging and the outcome of those talk influence the future of this code base.