Add certificate feature to app

[pontusBerg]

@amakodev

I sketched out a wireframe of how I see this feature working in the app.

• We add a new sidebar item called "Certificates"
• It displays all the certificates the user has
• We also add a share button for LinkedIn etc.

Let me know what you think. And if this is the intended way.

[amakodev]

Looks great. I can prepare the endpoints to get a user list of certificates and the data to be displayed. will provide the documentation, but in the meantime, the UI can be updated.