Revamp list's header

[slemeur]

As part of the work done to simplify the list and grips in UD.
We needt improve the way we are displaying description of UD's sections.

Here is the design:

Labels of each pages:
Dashboard:
Access your recently used workspaces and Factories, or create a new workspace. Clicking on your user name at the bottom will open up account and (with sufficient permissions) administration settings.

Workspaces:
A workspace is composed of projects, environments and commands. Create a new workspace or manage an existing workspace (start, stop, reconfigure or delete). Learn more.

Learn more will redirect to:
https://eclipse-che.readme.io/docs/environments

Administration:
Control the configuration and policies for your installation.

[ashumilova]

Resolved