Document Workflow Logic

[musslick]

Include general documentation about state logic

• [x] Depends on https://github.com/AutoResearch/autora-core/issues/65
• [x] There also needs to be a general start point about the introduction: https://github.com/AutoResearch/autora-core/pull/68

[hollandjg]

I've added some additional user guide pieces on the CLI in #612 (and associated PRs in the autora-core repo).

• 612

[hollandjg]

Done!