Move/redirect Jira Cloud API token page

What does this MR do and why?

• Moves https://docs.gitlab.com/ee/integration/jira/jira_cloud_configuration.html to https://docs.gitlab.com/ee/integration/jira/configure.html as an H2 heading. https://docs.gitlab.com/ee/integration/jira/jira_cloud_configuration.html contains a single task topic to create an API token for the Jira integration in Atlassian Cloud.
• Redirects https://docs.gitlab.com/ee/integration/jira/jira_cloud_configuration.html to https://docs.gitlab.com/ee/integration/jira/configure.html as noted in the documentation style guide.

Follow-up

• An MR in gitlab-docs to remove the left nav entry for https://docs.gitlab.com/ee/integration/jira/jira_cloud_configuration.html.

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