chore: rename manager/member to administrator (#11542)

# Which Problems Are Solved

As part of the naming consistency initiative, the terms `Manager`,
`Member` and other similar terms that are used in the context of an
administrator are replaced by `Administrator` in the UI and
documentation.

# How the Problems Are Solved

By replacing the following terms with Administrator / Administrator
Roles in docs, Console UI, and guides.

- Manager
- Add Manager
- Add a Manager
- Administrator (used as a person type)
- Membership
- Member grants

# Additional Changes
minor grammatical edits in the docs

# Additional Context
- Closes https://github.com/zitadel/zitadel/issues/11291

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Co-authored-by: Marco A. <[email protected]>

apps/docs/content/guides/integrate/actions/testing-function.mdx

@@ -10,7 +10,7 @@ This is useful for integrating with other systems which need specific claims in
 
 Before you start, make sure you have everything set up correctly.
 
-- You need to be at least a ZITADEL [_IAM_OWNER_](/guides/manage/console/managers)
+- You need to be at least a ZITADEL [_IAM_OWNER_](/guides/manage/console/administrators)
 - Your ZITADEL instance needs to have the actions feature enabled.
 
 <Callout>