Consistent indented text/elements style of border

[jrbarnes9]

All indented text/elements should follow a consistent style of border

Includes:

• onsTextIndent
• onsCollapsible
• Borderless onsRadios and onsCheckboxes with conditionally revealed input, select, checkboxes, radios

For the border colour, should we use the variable assigned to$color-borders or assign a lighter shade as a new variable?

Current onsTextIndent:

Current onsCollapsible:

Example of borderless onsRadios with conditionally revealed input:

For an example of borderless onsCheckboxes with conditionally revealed checkboxes see #1648

Originally posted by @jrbarnes9 in #233 (comment)