Refactor to group abstract operations per section for NumberFormat and DateTimeFormat

[caridy]

Disclaimer: This PR does not modify any algo, we just reshuffle them for organizational purposes.

Reasoning

• "Number Format Functions" holds several abstract operations, and it was a sub-section under "Properties of the Intl.NumberFormat Prototype Object", which is confusing, specially once we add more properties to those objects that could call the same abstract operations. The same applies to "DateTime Format Functions".
• InitializeNumberFormat() and InitializeDateTimeFormat() abstract operations were under the corresponding constructor section.

Notes

• moving all abstract operations of NumberFormat Objects into an abstract sub-section
• moving all abstract operations of DateTimeFormat Objects into an abstract sub-section.

Render Version:

• https://rawgit.com/caridy/c80267817f2736db7de8/raw/f7df1b2c9de232a69dbcf9e6e4eceb6966fb9eeb/ecma-402-pr1.html#numberformat-objects

[zbraniecki]

+1.

Cool! Let's land it before we move forward with revision 3 changes.

[rwaldron]

@caridy this LGTM, thanks for putting in the time and effort to make these changes