telemetry: add tracing

- telemetry/tace: add traces throughout code
- telemetry/metrics: nest metrics and trace under telemetry
- telemetry/tace: add service name span to HTTPMetricsHandler.
- telemetry/metrics: removed chain dependency middleware_tests.
- telemetry/metrics: wrap and encapsulate variatic view registration.
- telemetry/tace: add jaeger support for tracing.
- cmd/pomerium: move `parseOptions` to internal/config.
- cmd/pomerium: offload server handling to httputil and sub pkgs.
- httputil: standardize creation/shutdown of http listeners.
- httputil: prefer curve X25519 to P256 when negotiating TLS.
- fileutil: use standardized Getw

Signed-off-by: Bobby DeSimone <bobbydesimone@gmail.com>

internal/httputil/test_data/cert.pem

@@ -0,0 +1,10 @@
+-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----

internal/httputil/test_data/privkey.pem

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIMQiDy26/R4ca/OdnjIf8OEDeHcw8yB5SDV9FD500CW5oAoGCCqGSM49
+AwEHoUQDQgAEFumdSrEe9dnPEUU3LuyC8l6MM6PefNgpSsRL4GrD22XITMjqDKFr
+jqJTf0Fo1ZWm4v+Eds6s88rsLzEC+cKLRQ==
+-----END EC PRIVATE KEY-----