Improvements to automated builds

[iranl]

Description:

• Embed the build date in the binary using Config.h
• Show build date on Web configurator OTA
• Automatically number beta and master/nightly builds using Config.h. First beta for each version will be 9.0-beta1, second 9.0-beta2 and 9.0-master1/9.0-master2, auto resets to 1 on new version (e.g. 9.01-beta1)
• Store (OTA/Webflash) binaries in an orphaned branch called binary instead of in master. Prevents unbridled growth in size and commits of master

PM: Binaries need to be uploaded to master manually one more time after merge to make sure that users that auto-update from current development build get a version with the new URLs

PM2: Remove binaries from master (remove OTA and webflash directories) in a couple of months

Checklist:

• The pull request is done against the latest master branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works
• I accept the CLA.