More conversion options

[trymeouteh]

Would like to suggest some more conversion options

• Currency (fiat, gold, silver, goldbacks, crypto) Add currency converter #16
• Timezones
• Fuel Consumption
• Numerial systems
• Energy
• Power
• Angles
• Shoe Size
• Torque

Some of these conversions are in the Convert NOW app which is also written in dart
https://github.com/ferraridamiano/ConverterNOW