Issues in CI/CD for APIs docs

Description

Due to the following issues, first-time users of this scenario will need to search a lot and figure out the concerns on their own

Doc link: https://apim.docs.wso2.com/en/latest/install-and-setup/setup/api-controller/ci-cd-with-wso2-api-management/#page-header

1. The Heading repeated twice or it is not properly formatted.
   

2. Building a CI/CD Pipeline for APIs using the Jenkins link is not directing to the correct doc. It should be routed to https://apim.docs.wso2.com/en/latest/install-and-setup/setup/api-controller/building-jenkins-ci-cd-pipeline-for-dev-first-approach/
   

Doc Link : https://apim.docs.wso2.com/en/latest/install-and-setup/setup/api-controller/building-jenkins-ci-cd-pipeline-for-dev-first-approach/#step-1-write-the-openapi-specification-and-test-scripts

1. Screenshots of https://apim.docs.wso2.com/en/latest/install-and-setup/setup/api-controller/building-jenkins-ci-cd-pipeline-for-dev-first-approach/#prerequisites section need to be updated

2. To perform step-4 of https://apim.docs.wso2.com/en/latest/install-and-setup/setup/api-controller/building-jenkins-ci-cd-pipeline-for-dev-first-approach/#step-6-trigger-jenkins-pipeline we need to install the Jenkins plugin to the local Jenkins server. If not the pipeline option will not display in the jobs and that will confuse the user.
   

3. Add more images in the flow for better usability.
   eg:
   

4. We can remove the console outputs screenshots and provide them as text as it is a bit long

Start with the two linked API Controller documentation pages and compare the repeated heading, Jenkins link, prerequisite screenshots, and pipeline instructions. Check that the Jenkins plugin requirement and additional flow images are covered, and replace the long console-output screenshots with text where requested. Done means the links, formatting, screenshots, and user guidance are corrected on both pages.