Documentation about client generation some improvements that should be added

[Grummfy]

Hello,
I think some improvement is required on the documentation about client-generation (so /create-client)

1. All page in this section should have a link to the troubleshooting page (/create-client/troubleshooting/)
2. The troubleshooting page should have some extra elements

• # Authenticated API forget to tell that that the generator now include --bearer or --username & --password options. And perhaps being more explicit about which endpoint should be accessible or not (and link to the doc the page of configuration if required)
• A general advice on using --help could also ease some solution

3. Add example of generated files (if it exist, I miss them)
4. Add example of custom template for existing generator (it's possible but except if we read the code, I don't think it's really usable)

Should I create separated issue for that? I will try to find some times to add some of theses elements in the doc

[vinceAmstoutz]

@Grummfy You're welcome to contribute, check our CONTRIBUTING.md and submit your suggestions. Thanks!