to be fetched from the server before triggering OMEMOInitialized.
For some contacts, the IQ to fetch the device list never receives a
response. IQ stanzas take 20 seconds to timeout, which means that all
OMEMO operations are blocked for 20 seconds (because everything waits
for `OMEMOInitialized`).
Create a new API method `api.omemo.devicelists.get` and use that to
fetch and `await` for any devicelist. That way we lazily wait for
devicelists to be fetched from the server and can continue with other
OMEMO operations unrelated to users who's clients don't respond to
devicelist queries.
When calling `getDeviceList`, wait for the devices to be fetched
Otherwise a race condition might occur, whereby a new device gets
created in the collection, and then removed again as the collection is
replaced with the values fetched from the browser-storage cache.
Also created `converse-omemo-fingerprints` component to asynchronously
render fingerprints in the user details modal. Was done as part of this
commit because due to `getDeviceList` being async, the relevant test for
the modal were also failing
