Fetch up to 2000 list items, refactor list edit components

[blowery]

Changes proposed in this Pull Request

• Fetch up to 2000 list items in the initial pass
• Refactor the list edit components into functional components and add a loading indicator for the list items
• Always show the export tab, disable the button if we have not loaded the list items yet

Testing instructions

• Load a list with more than 10 items. Verify that all 10 items appear.
• Verify that a loading indicator appears on the /items section while loading the items
• Verify the export tab appears instantly along with the Sites and Details tabs
• Load the export tab directly on a long list and a slow network. Verify that the button is disabled while the list items load and enabled once loaded if there are items in the list.

[matticbot]

Test live: https://calypso.live/?branch=update/fetch-more-list-items

[matticbot]

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

Async-loaded Components (~219 bytes added 📈 [gzipped])

name                                        parsed_size           gzip_size
async-load-calypso-reader-list-manage           +1224 B  (+4.4%)     +189 B  (+2.5%)
async-load-calypso-reader-sidebar                -357 B  (-0.6%)      -75 B  (-0.5%)
async-load-design-blocks                         +200 B  (+0.0%)      +48 B  (+0.0%)
async-load-calypso-reader-following-manage       +200 B  (+0.2%)      +42 B  (+0.1%)
async-load-calypso-reader-list-stream            +122 B  (+0.9%)      +15 B  (+0.4%)

React components that are loaded lazily, when a certain part of UI is displayed for the first time.

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.

[jsnmoon]

Works as described.

It would be nice to add a loading indicator to the export page in the future while ListItems are being loaded.

[blowery]

@jsnmoon

It would be nice to add a loading indicator to the export page in the future while ListItems are being loaded.

done

also added missing list detection and translations

[a8ci18n]

This Pull Request is now available for translation here: https://translate.wordpress.com/deliverables/5094392

Hi @blowery, could you please edit the description of this PR and add a screenshot for our translators? Ideally it'd include all of the following strings:

• DANGER!!
• DELETE LIST FOREVER

Thank you in advance!

[a8ci18n]

Translation for this Pull Request has now been finished.