website/download: update daily snapshot section

This patch makes some minor changes to the download page of the website:
- don't capitalize Daily Snapshots as there is no reason to.
- remove extra link to daily snapshots, as this link is already available on
  the line below.
- add a link to the latest snapshot
- avoid 'Click here', especially if 'here' is not clickable

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>