make downloads consistent per perstistence layer

[vg-leanix]

Current Situation

1. Task is triggered
2. Task is inserted to VUEX and written to table /downloads
3. Websocket from MongoDB updates status

Problem
list is exposed via LocalStorage
inconsistent use of MongoDB -> should be the only persistence layer

Possible Solution

1. On page load load last 5 downloads from MongoDB
2. for newly triggered tasks:
3. use websocket event to pull new data from MongoDB ( either via API call or using websocket event data directly)