In shared menu: add number of news (projects and artifacts)

[jdirocco]

No description provided.

[jdirocco]

Artifact behaviour:
User1 shares Artifact1 to User2;
User2 see Artifact1 in shared artifacts page in (https://dashboard.mdeforge.org/private/shared_artifacts/),
User2 add Artifact1 to one of his projects.
User2 doesn't see Artifact1 in shared artifact page

Project behaviour:
User1 shares project1 to User2;
User2 see project1 in shared projects page in (https://dashboard.mdeforge.org/private/shared_projectss/),
User2 add project1 to one of his workspaces.
User2 doesn't see project1 in shared project page