Added support for numeric values

[Triqueon]

I've added a special handling case for templated values that look like numbers: digits potentially preceded by a minus sign, possibly followed by a '.' and more digits, possibly followed by 'e' and more digits, and converted them to a float. I don't think this will cause any trouble, as there shouldn't be any cases where a card expects a string and can't deal with a number, but the reverse isn't true; the gauge card, for example, refuses to work with a templated value as it expects a number.

If there is a problematic case I have overlooked, a potential solution would be to implement a check for a pseudofunction, i.e. templated values matching {{numeric(some_value)}} get converted to floats.

[gadgetchnnel]

Thanks for this, looks good 👍