This commit adds a new logging instrumentation. The instrumentation
patches standard library logging module to inject tracing context
variables (otelSpanID, otelTraceID, otelServiceName) into log record
objects. It also optionally calls `logging.basicConfig()` and sets a
logging format that makes use of these vars if instructed by the user.
OpenTelemetry doesn't support Python 2.7. Removing it from the tests and removing contrib packages that don't support Python 3. In this change:
- removing pylons contrib
- removing mysqldb contrib
- updating minimum versions of flask (>=1.0), gevent (>=1.1)
Signed-off-by: Alex Boten <aboten@lightstep.com>
