Page buttons background follows @breadcrumb-bg value

@breadcrumb-bg variable available currently in the "Breadcrumb" section of the theme configuration changes color for both breadcrumb background as expected, but also the page buttons.

This misleading as:

• These two elements don't target the same type of content in the page
• These two elements can be managed separately for a theme customization
• These two elements don't share the same foreground color variable for text/links
• Page buttons have the "btn-default" class and yet don't apply the @btn-default-bg variable.

Example:

Expected:

• To have two variables to these two elements.
• Eventually the existing @btn-default-bg variable could be used for page buttons?