8.0 num2words Number to Words for QWEB

Options
``` 1 - <t t-esc="1234" t-esc-options='{"widget": "num2words"}'/>
 2  - <t t-esc="1234" t-esc-options='{"widget": "num2words","case":"upper"}'/>
   3 - <t t-esc="1234" t-esc-options='{"widget": "num2words","case":"lower"}'/>
   4 - <t t-esc="1234" t-esc-options='{"widget": "num2words","case":"capital"}'/> ```
use a dict to map cases to operations, or at least use elif, no need to check if `case == 'lower'` if `case == 'upper'` has already been executed