📚 Revamped documentation!

[lowlighter]

Following #771 and #778, the whole documentation has been rewriten to be cleaner, up-to-date and use a more neutral writing style.

In addition to a less bloated README.md, plugins and templates documentation are now auto-generated from their metadata.yml and workflow examples.yml (the later also being used for testing, ensuring that given examples are always working).

Plugin documentation

• includes supported templates, account types, required scopes
• includes actual workflow examples
• options are now displayed directly on the main page, along with typing, default, allowed values, properties and description

Template documentation

• includes supported plugins, account types, output format
• includes actual workflow examples

Overall documentation

• cleaner and less bloated
• easier on-boarding with clear advantages and use-cases for different kind of setup