Add link to online docs

[ElliottKasoar]

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PR author must check the checkboxes below when creating the PR.

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Summary

Adds details drop down, currently containing a hyperlink to the relevant docs, but we can extend this to other info, if we are ok with duplicating some text.

Linked issue

Resolves #5

Alternatives

I also looked into https://www.dash-bootstrap-components.com/docs/components/collapse/, but this seems to require using the bootstrap style, or importing the relevant JavaScript.

[coveralls]

Pull Request Test Coverage Report for Build 18162793830

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.02%) to 2.256%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
ml_peg/app/base_app.py	0	1	0.0%

Totals
Change from base Build 18109276578:	-0.02%
Covered Lines:	3
Relevant Lines:	133

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💛 - Coveralls

[ElliottKasoar]

For context, this looks like:

It is also optional.

We can add something similar for categories if we'd like, but currently there's no specific information to link to, so we can do it later.