Require explicit answer in SH license prompt

[jaimergp]

Description

Closes #721

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[jaimergp]

Tried locally and this is what you get now:

The License has to be read correctly so that dollar signs don't lead to an unset
parameter error:
You have to pay US $8, if you can read this.


Do you accept the license terms? [yes|no]
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> 
Please answer 'yes' or 'no':'
>>> n 
Please answer 'yes' or 'no':'
>>> no
The license agreement wasn't approved, aborting installation.