Docsy/User-guide "skin" styles should be factored out and/or dropped in some cases

[chalin]

This issue is a part of:

• Support easy disabling of Docsy styles for HTML elements #1431

Docsy has essential (including flow-related and spacing) styles, and other style changes that we might consider a Docsy/User-guide "skin" -- such as choices for colors, preferred table formating, etc:

docsy/assets/scss/_variables.scss

Lines 8 to 18 in d30b1c9

	// TODO: consider moving all of these theme-color definitions into the User
	// Guide SCSS, or declare theme here, but namespaced:
	$primary: #30638e !default;
	$secondary: #ffa630 !default;
	$success: #3772ff !default;
	$info: #c0e0de !default;
	$warning: #ed6a5a !default;
	$danger: #ed6a5a !default;
	$light: #d3f3ee !default; // TODO: consider using BS value
	$dark: #403f4c !default; // TODO: consider using BS value

Another example is this button styling:

docsy/assets/scss/_buttons.scss

Lines 3 to 15 in d30b1c9

	@if $enable-rounded {
	.btn {
	border-radius: 1rem;
	&-lg {
	border-radius: 2rem;
	}
	&-sm {
	border-radius: 1rem;
	}
	}
	}

Right now, it is a challenge for projects to opt out of these "skin" styles, since they need to address each style change individually.

• Use Bootstrap's default link style, which is recommended  #1814