Do not use tokens that look like tokens in docs

What does this MR do?

Do not use tokens that look like tokens in docs. Replace 9koXpg98eAheJpvBs5tK with <your_access_token> throughout the docs.

Command used:

find ./doc -type f -exec sed -i 's/9koXpg98eAheJpvBs5tK/<your_access_token>/' {} \;

Related issues

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/38064

Author's checklist

• Apply the correct labels and milestone
• Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8973

Review checklist

• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8973