Fix structured data price rounding issue and usage warning

[Jore]

Fix rounding issue caused by using divided_by Math filter.
> Divides an output by a number. The output is rounded down to the nearest integer.

i.e. 3499.95 was being rounded down to 3499
See: https://help.shopify.com/themes/liquid/filters/math-filters#divided_by

Bring price implementation inline with usage guidelines. No longer produces warning in Google's Structured Data Testing Tool for values greater than 999.99 that use comma separator for readability.

> Use '.' (Unicode 'FULL STOP' (U+002E)) rather than ',' to indicate a decimal point. Avoid using these symbols as a readability separator.

See: http://schema.org/price

Updated pull request based on solution in comments provided by @cshold

[cshold]

We've updated this on some of our other themes and used divided_by: 100.00 — specifying the decimals will tell it what to round to. Using remove isn't usually a great fix because of how many different currency types there are.

[Jore]

Fair call with different currency types. I have revised the pull request with divided_by: 100.00.

Much better solution, thank you.

[cshold]

Thanks for the PR and the update. 👍