Create dropdown menu for main navigation

[gsambrotta]

Main menu (header, top right) item "Community" and "About" should have dropdown menu. Design is still to be decided but should be in line with the main header and in general with OTS style/colors.

Items that goes under "About" are:

• History
• Projects
• Where we operate
• What drive us
• Contact

Items that goes under "Community" are:

• Chapters
• Projects
• OTS People

"Projects" and "OTS People" will have a secondary menu inside the page, as "page header" (not dropdown): "Projects"

• Regular events
• Projects
• Contribution

"OTS People"

• Ots Stories
• How we think eduction should be
• Why be part of OTS Community
• Get in touch with us

Step to achive task:

• create dropdown menu design/style
• create page under main menu and connect to it
• create "page submenu" design/style
• create "page submenu" page (new created page could be empty or with just a title)

Note: When submit the PR, please attach also picture to show the intended design.

[gsambrotta]

We could also think about a menu link the one in this website: http://brownsardina.com/

So we have no usual usability problems coming from dropdown menus