[IDEA] Have only one footer region for blocks?

Problem/Motivation

Footer layouts varies widely from client to client. Usually we need to add additional CSS that is overriding default layout rules. It would be hard to add SASS variables that would make this more flexible, additionally having SASS variables still requires some developer to change them and recompile CSS.

Proposed resolution

Idea is to have only one region in the footer, so remove 'Footer Second' and keep just 'Footer' region. Then load needed Bootstrap layout utility responsive classes for controlling grid column width and margins and padding, or provide our own limited set of CSS classes for this - site builder would then use this utility classes to achieve desired responsive layout structure.
Benefits of this approach are:

• This would allow site builders to fully control footer layout
• No more need for frontend developers to tweak footer layout, they could do something else :)
• We can drop related footer layout CSS code
• If we ever decide to test paragraphs in footer approach then it is easier to done this with just one footer region.

Remaining tasks

Decide should we do this first.

We would need to document all CSS classes that can be used for this, and provide clear examples for most common cases.

Default installation should provide default blocks which layout structure is the same like it is now.

Doing this would mean we make https://www.drupal.org/project/block_class contrib module a dependency, but I guess this is fine.