[bugfix] Align default values in the configuration file with the code

[firescry]

Description

If this is a code change, please include a summary of what you've coded, and link to the issue(s) it closes/implements.

If this is a documentation change, please briefly describe what you've changed and why.

This pull request aligns default values defined in example/config.yaml and in internal/config/defaults.go - in most cases changes are done to the config file.
There is one exception where default value is added to defaults.go - it is for AdvancedThrottlingRetryAfter variable introduced as part of #1466.
Also snippets of config.yaml file are updated in the documentation.

Closes #1964

Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: [ ] -> [x]

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

• I/we have read the GoToSocial contribution guidelines.
• I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
• I/we have performed a self-review of added code.
• I/we have written code that is legible and maintainable by others.
• I/we have commented the added code, particularly in hard-to-understand areas.
• I/we have made any necessary changes to documentation.
• I/we have added tests that cover new code.
• I/we have run tests and they pass locally with the changes.
• I/we have run go fmt ./... and golangci-lint run.

[daenney]

I think this looks pretty good, and it's honestly something I'd be fine with merging in the RC-cycle as it fixes a bunch of erroneous values in example/config.yaml. We tell people to review and adopt those values when upgrading, so right now a bunch of instances are probably slightly misconfigured.

@tsmethurst what do you think?

[firescry]

Thanks for the review! 😊

I set it as "ready for review" in case you would like to merge it as it is.

[tsmethurst]

This is helpful, thank you!

[tsmethurst]

Kapow!