ci(main): consolidate workflows into main.yml; add beta support

[dancormier]

SPARK-9

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This PR consolidates the release.yml and workflow.yml workflows into a single workflow named main.yml. It also adds support for beta releases.

A few important details

• I hastily committed some workflow experiments directly to the develop branch yesterday. I've reverted them to for the sake of safety and cleanliness
• This PR lifts heavily from https://github.com/StackExchange/Stacks-Editor/blob/main/.github/workflows/main.yml
• It might be best letting this PR hang out for a little while while we integrate stacks-svelte into the monorepo setup. I don't expect any significant issues with having this PR pending merge for a little while.

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Latest commit: d1289c1

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