Add vulnerability section into scenarios page

[stufraser1]

Scenarios lacks any information on what vulnerability functions have been used to estimate loss.

This requires:

• documentation in User Guide (placeholder section being added), incl. instruction on how change in vulnerability can be made (out of tool), whether different V functions can be applied or not.
• Clear information in the main page (analysis set up / scenario selection), identifying the vulnerability being used / enabling selection of different curves
• Clear information on Comparison to describe which vulnerbaility curves are being used in each analysis.