Cleaning up some errors in the javascript console before I start adding new ones.
src/js/ConfigStorage.js: forgot to test writing multiple keys at once, can now write multiple keys at once.
src/js/FirmwareCache.js: avoid throwing an error if someone comes asking for an undefined firmware
src/js/jenkins_loader.js: same .error deprecation as #1568
Due to regular quotes being used in `jenkins_loader.js` instead of backticks the current JobsData is cached as
"${viewUrl}JobsData"
"${viewUrl}JobsLastUpdate"
Instead of something like:
"https://ci.betaflight.tech/view/Firmware_JobsData"
"https://ci.betaflight.tech/view/Firmware_JobsLastUpdate"
Another idea would be to do "jenkinsJobsData" and "jenkinsJobsLastUpdate" to match with the other cache keys
I've chosen to add an underscore in between the URL and the rest of the key to make it easier to look at.
