[Major]: Remove Moment and Node 10

[snewcomer]

close #69

Considerations

Dates can be compared either with getTime or if in string format, we can compare "11/2/2014 < "11/3/2014".

• remove String 'now' argument.
• remove momentjs
• Remove precision argument. If you need to compare based on precision, you can use the Intl.DateTimeFormat APIs to hone in on the comparison - { year: 'numeric' }. Even { dateStyle: 'full' } works!
• Added locale option. Defaults to en-us when creating date times. This is probably less useful for the actual on/before/after but it can help in formatting your error message.

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Some other options

• Just install date-fns
• Configurable date-fns
• Raw Intl APIs

In any case this will require a change in the format argument.

e.g. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/format

• Note, I did my best with the short amount of time I looked at this + without an actual use case to test. Please let me know if there is something I missed!