Add context path info to component REST APIs

[tmetzke]

Description

Adds details on where to find the Zeebe, Tasklist, and Operate REST API endpoints.
Backported until version 8.2 where applicable.

closes #3698

When should this change go live?

• This change is not yet live and should not be merged until {ADD_DATE} (apply hold label or convert to draft PR)?
• There is no urgency with this change.
• This change or page is part of a marketing blog, conference talk, or something else on a schedule.
• This functionality is already available but undocumented.
• This is a bug fix or security concern.

PR Checklist

• I have added changes to the relevant /versioned_docs directory, or they are not for an already released version.
• I have added changes to the main /docs directory (aka /next/), or they are not for future versions.
• My changes require an Engineering review, and I've assigned an engineering manager or tech lead as a reviewer, or my changes do not require an Engineering review.
• My changes require a technical writer review, and I've assigned @christinaausley as a reviewer, or my changes do not require a technical writer review.

[tmetzke]

@ralfpuchert and @houssain-barouni, can you please check if the changes are correct for Operate and Tasklist?
Please especially have a look at the changes to the released versions regarding context paths that might have changed, e.g. from /api/v1 to /v1 or anything alike.

[tmetzke]

@jonathanlukas, can you please double-check that this is what you're looking for? 🙂

[jonathanlukas]

lgtm

[ralfpuchert]

Operate public API has been available under /v1/. LGTM

[houssain-barouni]

LGTM for tasklist

[tmetzke]

Thanks, @christinaausley, for your additions, super helpful for the users! 🌟