New directory for OpenTelemetry QuickStart

[aravinsiva]

Most files are the same from cloud-trace-demo-app. The ones that have been modified to support the opentelemetry framework are as follows:

• README.md
• app.py
• app.test

Corresponding QuickStart docs can be found here:
(https://cloud.google.com/trace/docs/quickstart

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[busunkim96]

@aravinsiva If you are a Googler, make sure to register your GitHub account with Google Open Source. If you're an external contributor, please sign the CLA.

[googlebot]

CLAs look good, thanks!

ℹ️ Googlers: Go here for more info.

[busunkim96]

LGTM from my end. I assume there's still work pending before this can be merged? (the -e ... installs in the requirements.txt)

[sjbrunst]

One outstanding comment, otherwise LGTM

[leahecole]

LGTM since @sjbrunst is happy