Remove Tender and change Studio help links.

cms/djangoapps/contentstore/features/help.feature

cms/djangoapps/contentstore/features/help.py

cms/envs/aws.py

cms/envs/bok_choy.py

cms/envs/common.py

cms/envs/test.py

cms/static/cms/js/build.js

cms/static/cms/js/require-config.js

cms/static/coffee/spec/main.coffee

cms/static/coffee/spec/main_squire.coffee

cms/static/js/base.js

cms/static/sass/_build.scss

cms/static/sass/elements/_sock.scss

cms/static/sass/elements/_tender-widget.scss

cms/templates/activation_invalid.html

cms/templates/base.html

cms/templates/error.html

cms/templates/index.html

cms/templates/login.html

cms/templates/widgets/footer.html