Use single traceviewer lib subtree

[marcdumais-work]

What it does

Rough instructions how this was done:

theia-trace-extension

1) rename packages to traceviewer-libs
note: had to do this after splitting the libs as subtree - else the git history was not picked-up correctly, resulting in a subtree with a single commit. 
rename packages folder to traceviewer-libs
    
This will make for a nicer, more descriptive name for the
splitted-out git subtree that will contain the two libraries
    


2) split-out tracewviewer-libs:
git subtree split --prefix=packages --branch traceviewer-libs
git checkout traceviewer-libs
git remote add traceviewer-libs git@github.com:marcdumais-work/traceviewer-libs.git
git push traceviewer-libs traceviewer-libs:master

3) add traceviewer-libs as subtree in vscode-trace-extension:
git subtree add --prefix=traceviewer-libs traceviewer-libs master --squash

How to test

Follow-ups

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the instructions in this template