chore: remove recommended fallback if there is a config

[tatomyr]

What/Why/How?

Currently we provide the default fallback with the recommended ruleset if there's no extends explicitly set up in a Redocly config file or there's no config file at all.

We put a deprecation message some time ago, and now it's the highest time to finally change the approach: to extend with the default ruleset ONLY when there's no config provided.

Also it would be great to remove the deprecated suggestions (like apiDefinitions &c.).

• change default fallback behaviour
• check configs for braking changes
• remove deprecated suggestions

Reference

Testing

Screenshots (optional)

Check yourself

• Code is linted
• Tested with redoc/reference-docs/workflows
• All new/updated code is covered with tests

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	73.41%	3285/4475
🟡	Branches	64.99%	1832/2819
🟡	Functions	66.39%	555/836
🟡	Lines	73.32%	3051/4161

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🟢	... / config-resolvers.ts	86.21%	75.1% (-1.48% 🔻)	100%	86.33%

Test suite run success

509 tests passing in 84 suites.

Report generated by 🧪jest coverage report action from 0b4b97c

[tatomyr]

Closing this in favor of #923