2.7.2rc14: Feature improvements and documentation updates

What's Changed

• [2.7] add device_wait_timeout to ET class by @ZiyueXu77 in #4273
• [2.7] Enhancements on CI install_requirements by @YuanTingHsieh in #4249
• [2.7] Scaffold update: defensive check; docstring update by @holgerroth in #4279
• [2.7] 2.7.2 documentation updates [skip ci] by @chesterxgchen in #4278
• [2.7] Fix external kill before server download by @YuanTingHsieh in #4275

Full Changelog: 2.7.2rc13...2.7.2rc14