* Create alertmanager.js
* Add changelog
* Rename contrib/alertmanager.js to contrib/jsTransformationFunctions/alertmanager.js
* Add docs to alertmanager.js
* Update alertmanager.js
* Update alertmanager.js with paragraphs
* Update alertmanager.js
convert `\n` line breaks to html `<br/>` so the upstream formatting is applied
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Co-authored-by: Will Hunt <will@half-shot.uk>