Created tree and files for the Web App doc

.gitignore

docs/components/custom-apps/web-app/changelog.md

docs/components/custom-apps/web-app/contact.md

docs/components/custom-apps/web-app/credits.md

docs/components/custom-apps/web-app/dataset/data.md

docs/components/custom-apps/web-app/dataset/info.md

docs/components/custom-apps/web-app/dataset/resources.md

docs/components/custom-apps/web-app/drafts.md

docs/components/custom-apps/web-app/feedback.md

docs/components/custom-apps/web-app/footer.md

docs/components/custom-apps/web-app/header.md

docs/components/custom-apps/web-app/homepage.md

docs/components/custom-apps/web-app/overview.md

docs/components/custom-apps/web-app/partners.md

docs/components/custom-apps/web-app/reuses.md

docs/components/custom-apps/web-app/search.md

docs/components/custom-apps/web-app/side-menu.md

docs/components/custom-apps/web-app/sign-up-in-out.md

docs/components/custom-apps/web-app/static-pages.md

docs/features/index.md