Slow loading of webviews of trace viewer

[bhufmann]

Bug Description:

It takes noticeable time till the webviews are populated at startup and when a trace is opened. A quick assessment shows:

1. vscode platform takes time to download (from the extension) the javascript file of each webview (e.g. trace_panel.js).
2. Many BE queries are sent at the beginning when opening a trace where some seem to be redundant.

Investigate how the startup time can be improved, i.e. loading of javascript files and amount of BE queries sent.

Steps to Reproduce:

1. Open VSCode
2. Open Web developer tools and its network tab
3. Open Trace Viewer
4. Open trace

After step 3 will take some time to populate the TRACES view.
After step 4 it will take a noticeable time till VIEWS view is populated.
After step 5 it takes time till the trace viewer panel is populated with the overview view

Check the timing in the network tab of the developer tools to confirm the loading time and sent messages.

Additional Information

• Operating System: Ubuntu 22.04
• VSCode Version: 1.105.1