Look for ways to better reuse renderers across UI frameworks

[richard-jones]

• PR: [when the PR is created, put a link to it here. DO NOT use the "linked PR" feature]

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Renderers are mostly HTML and have a set of behaviours attached to them. For the most part the difference between, say, BS3 and BS5 are minor, but in the current approach two complete copies are required. Is there a way to reduce the amount of actual code duplication and just focus on the specifics of the CSS framework?

Acceptance Criteria

• Code duplication is minimised between CC framework