Reconfigure Restyled

[lucydodo]

This PR reconfigures Restyled, which was currently used as a linter.
For consistency with the original repo, I have referenced the configruation files from the original repo: https://github.com/getredash/redash/blob/master/.restyled.yaml

Feel free to leave any comments or reviews. Thank you.

[lucydodo]

FYI: When this PR was merged, I closed the following PRs in advance to avoid conflicts with existing configuration.

• Restyle Update dashboard api doc to use the id instead of slug #478
• Restyle Update mongodb.md #480
• Restyle update query for Elasticsearch 7.x #481
• Restyle Add verify option to allow query developers to skip SSL certificate … #515
• Restyle Update signup #582
• Restyle add indent keyboard shortcut #595
• Restyle [dev] Link to UI end to end tests #602
• Restyle [testing] Fix broken link to Cypress #604
• Restyle [testing] Generic link to Python virtual env docs #607
• Restyle docs: Minor tweaks to api.md #609
• Restyle Adding documentation for DataSource NewRelic #639
• Restyle Add Azure AD Oauth Instructions #659

[justinclift]

@eradman Do you know the linter syntax well enough to cast your eye over this? 😄

[justinclift]

Seems to be all good + approved, so I've just hit the merge button. 😄

[lucydodo]

Thank you both of you. :)