Add support for reuse configuration in OTA generator.

Use vuex to store the otaConfig, now the history configurations can be
reused in the job detail page. Also the targetBuilds, incrementalSources
are not stored in vuex as well. Once the targetBuilds are chosen, it
will not lose the states when switching the tab between singleOTA,
batchOTA and chainOTA.

Test: npm run test:unit
Change-Id: I563ac0c79fd0cedd5e71e8722b956545f6624551
8 files changed