Documentation issues - Githubissues

[x] Warn the user that the workflow gets triggered for each commit to master
[x] Add more granular triggers in the GH workflow (specific folder code) and comment the code. Describe in the documentation how the user can change the behavior of the workflow.
[x] Provide more details on how the secret can be setup
[x] Make the links to the AML Actions that are used more prominent. Users just scroll over them and do not find the actual documentation of our GH Actions.
[x] Instruct the user to comment out parts of the workflow, if he only wants to work on training and not deployment

machine-learning-apps / ml-template-azure