Improve the use of tooltips

• Help labels on forms are announced by being underlined, but it is the only place where it is working like this
• White big bubbles are displayed on content views but it is also a specific case
• Other interesting help is only displayed through the default tooltip style from browsers, with their own timing and look.

• use one library for all help messages, keeping control on timing + look
  We may need 2 different timing -> short for labels, longer for help paragraph like on content views.

See NXP-12072 to add tooltip on user id and usernames.