Datahub / map overlay when scrolling/dragging is not readable enough

[jahow]

See it live: https://dev.geo2france.fr/datahub/dataset/ded8164c-d56b-4ae0-b93d-459fc7c99a01

The overlay is not staying long enough and is not very readable, most likely leaving the user wondering what just happened.

Expected

• overlay appears quicker
• text background makes it more readable

[lucilecollignon]

• First of all, it should stay as long as the user did not tap or click.
• We should avoid mixing tips for touch device and for mouse device. So it would be nice to have a contextual text regarding to the device.
• Regarding lisibility, the background can be in white with a transparency and maybe the background-blur effect.