[KATC] Prepare ee/indexeddb for use in KATC tables

[RebeccaMahany]

Now that we have a KATC implementation here, we can prepare to implement an indexeddb_leveldb source type. This PR updates the ee/indexeddb package in preparation for KATC usage by doing the following:

• Remove data that we now know is superfluous (indexeddb key, indexeddb version)
• Rename deserializeIndexeddbValue deserialization function for consistency with deserializeFirefox
• Separate out the data retrieval function (QueryIndexeddbObjectStore) and transformation function (now deserializeChrome), and update their method signatures, so that they can become a katcSourceType.dataFunc and rowTransformStep.transformFunc, respectively