[META] Blocks Blocks Blocks

Meta issue to help keep track of all the block related issues and initiatives, including converting the existing custom blocks into fieldable entities and creating a new type of custom text block that can be added to layouts and saved in config.

Issues for implementing content blocks and custom blocks:

[x] Make reusable blocks into stand-alone blocks
[x] #100 ~~Add fieldable, reusable blocks system~~ Add a system of page-less nodes
[x] #1099 Add a custom [text] block
[ ] #1277 [META] [UX] Improve the overall creation and placement of custom blocks experience.
[x] #1428 Export reusable custom blocks to configuration
[x] #1515 Make stand-alone blocks into reusable blocks
[ ] #3995 [WP][UX] Dashboard: Collapsible blocks
[ ] #3996 [WP][UX] Dashboard: Dismissible blocks

Issues around adding blocks to layouts:

[x] #778 ~~[UX] Move node/add to content/add so additional entities like blocks can be listed there~~ Nixed per #1428.
[x] #1276 ~~Move custom block list to admin/content/block~~ Nixed per #1428.
[ ] #1277 [UX] Improve the overall creation and placement of custom blocks experience
[ ] #1360 [UX] Link to the Layouts admin page from the Custom blocks admin page.

Issues around block titles

[ ] #692 [UX] Make block titles required and allow them to be hidden.
[ ] #1522 [UX] Move 'Admin label' field below others on Add block form
[ ] #1889 [UX] Always include the "View: [view_name]: [block_display_name]" as the default admin label for blocks provided by views.
[ ] #2288 [UX] Replace the default description of custom blocks with an excerpt from the block content.
[ ] #2483 [UX] Consider replacing the block title type drop-down with an always required (and unique) block title field.
[x] #2723 Change where layouts obtains the title and description for a views block.
[ ] #3916 [UX] Blocks: Make the "Custom title" field required.
[x] #4558 [UX] Allow all blocks to have an admin label

Other block-related issues:

[ ] #198 Move menu blocks into menu module (out of system.module)
[ ] #212 Remove the block cache from Backdrop
[x] #449 Create a list of blocks and the modules that provide them
[x] #570 Automatically remove blocks from layouts when a module is uninstalled
[x] #796 Convert page template elements into movable layout blocks
[x] #845 Add Menu Block features to core (feature parity with D8).
[x] #1076 Add ability to add "existing node" to a layout
[x] #1100 Add blocks for adding individual fields from entities
[x] #1228 In Dynamic block it adds unnecessary classes
[x] #1280 Allow Non-Region Layout UI regions
[x] #1340 [UX] Rename labels in add block page?
[x] #1373 Image files uploaded through custom block wysiwyg are removed by garbage collection
[ ] #2254 [UX] Prefix all menu block admin labels with "Menu:"
[ ] #2640 [UX] Make it clear in the manage blocks UI that title-only custom blocks without content will not be rendered.
[ ] #2667 [DX] the CSS class block-layout-custom-block disappears when a block becomes reusable
[x] #3994 [UX][WP] Dashboard block: Welcome to Backdrop CMS
[x] #5248 [UX] Create interface to organize Custom Blocks

backdrop / backdrop-issues

[META] Blocks Blocks Blocks #1427