Add support for syrup recipes (with ratio calculator)

[sbordeyne]

For my home bar (and for any home bar), we often have to make our own syrups because there is no commercially available cinnamon syrup, honey syrup, or other fancy syrups.

Making shelf-stable syrup is very straightforward : 2 parts sugar to 1 part water in a saucepan and just bottle it, it would be nice to have the integration into bar assistant to calculate the amounts of sugar and water required based on the ratio and desired total volume (math is very simple though : if V is the total volume and r the sugar/water ratio, S = r*V/(r+1) and W = V/(r+1))

Ratio should be variable (cause people might want to make a 1:1 simple or a 2:1 richer, shelf stable version, and for honey syrup the ratio is different since honey is not 100% sugar).

[sbordeyne]

sorry for categorizing that issue as a bug, I missclicked when creating it