Update blocks machine name to be prefixed by the theme machine name

Problem/Motivation

When placing block on a page, you can set the block machine name. But the configuration of this block depends on the theme you place your block in.

On the same websites, if there are multiple themes, you can't place the same block on another theme with the same machine name because it is already used.

Proposed resolution

Replace blocks machine name, for example:

core/profiles/demo_umami/config/install/block.block.languageswitcher.yml => core/profiles/demo_umami/config/install/block.block.umami_languageswitcher.yml

Remaining tasks

• Coder patch had been prepared: #3061184: Add a rule on block machine name
• Alter the autogenerated machine name in the form to add a block to prefix automatically by the theme machine name: #3061266: Prefix block machine name suggestions with the theme machine name
• Update all the existing block config in core to respect this new standard mainly in Umami (check for regression) and test modules/themes (this issue)