Add the website header and first routes

- Create the header in layout.jade, with a navbar pointing to 3 pages
(home, memories, projects)
- Remove the "title" variable from index route
- Add the route for memories page
- Start to design the index page
- Improve the CSS for the common header and the index page
Add a temporary template for memories page
Use the mongoose package to connect with a mongodb database and ignore the db files
Connection to db and display all blog articles from blogarticles collection
Add some style to articles