Add doc for the footer, fix link to folder structure in web app overview page, add uderline on '<a>' tags present in the main content of the documentation

Add doc for the footer, fix link to folder structure in web app overview page, add uderline on '<a>' tags present in the main content of the documentation

- Improved skeleton
- Improved Authentication Service documentation

update banner color using mkdocs.yml

add Dockerfile for mkdocs
add mkdocs.yml for mkdocs
add pip install mkdocs-material