1. Sync sphinx dependency with global requirements. It caps python 2 since
sphinx 2.0 no longer supports Python 2.7.
2. Remove unncessary "=="
Change-Id: Ic8d4ac21906dd78159375a51fc7514f8d664f22a
1. Update URLs according to document migration
2. Update the dead and outdated links
3. Optimize (e.g. http -> https)
Change-Id: Icd6b6b3e738d615a406120d302453a04751c199d
Use https instead of http to ensure the safety without containing our
account/password information
Change-Id: I48ac6c37b0abb4c14e6803f99abb57e275175eba