Make Help Desk email address less prominent in https://tails.boum.org/support/

During our helpdesk meeting today about the auto-reply issue, we have noticed that the email for the helpdesk team is quite easy to access from this page, and maybe it is too prominent, which makes more users decide to write to us rather than find help on our website.

For example, it is harder to find out how to report a bug, which is one click away and a very long set of instructions to use WhisperBack, or which are the known issues.

Maybe we can add this part of one of our templates before giving the email:

We are a very small team working on very limited human resources. So please, take this into consideration when writing to us...

We can also change 'write to us' with 'write to us if you didn't found answers in all previous resources'.

This change will help us to fulfill the new helpdesk mission and is related to #17935 (closed), but can be implemented before the auto reply.