Reach parity with shinydashboard

[osenan]

We want to have all components available on shinydashboard also on semantic.dashboard.

Right now four components/functionalities are missing:

• menuitems in sidebar should be collapsible #172 Collapsible menuItems for sidebar
• UpdateTabItems: I couldn't find this function in the semantic.dashboard library. #136 Function updateTabItem
• Add sidebarSearchForm #181 sidebarSearchForm
• Add sidebarUserPanel #182 sidebarUserPanel

Moreover to complete parity epic we could add two more features:

• Test to check that we have all functions form shinydashboard on semantic.dashboard
• Example demo with all shinydashboard and switch to semantic.dashboard components