Drop moment support from i18n-calypso.

[sgomes]

This PR gets rid of moment as a dependency of i18n-calypso, as nothing should be making use of that functionality anymore.

This will also be the final step in getting rid of moment in the login entry point, saving ~20KB (compressed).

Changes proposed in this Pull Request

• Remove i18n.moment
• Remove moment prop from i18n.localize
• Update tests and documentation accordingly
• Minor lint fixes
• Remove moment provider from login entry point

Testing instructions

It's hard to provide detailed instructions, since this could potentially affect any part of Calypso. I tried to go through and convert every usage of i18n-calypso's moment into something else in previous PRs, but I may have missed something.

[matticbot]

Test live: https://calypso.live/?branch=update/drop-moment-from-i18n-calypso

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

App Entrypoints (~20319 bytes removed 📉 [gzipped])

name                   parsed_size           gzip_size
entry-login               -73434 B  (-7.2%)   -19676 B  (-7.4%)
entry-main                  -136 B  (-0.0%)     -101 B  (-0.0%)
entry-domains-landing        -46 B  (-0.0%)     +200 B  (+0.2%)
entry-gutenboarding          +32 B  (+0.0%)     -742 B  (-0.1%)

Common code that is always downloaded and parsed every time the app is loaded, no matter which route is used.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[jsnajdr]

This is awesome 💙 Congrats for finishing the long journey!

[sgomes]

This is awesome 💙 Congrats for finishing the long journey!

Thank you for the review and for all your help along the way, @jsnajdr! I'll leave this for Monday, to avoid potential issues over the weekend.