Rename registry to provider

[dyladan]

Fixes #740

[dyladan]

pushed the wrong thing

[codecov-io]

Codecov Report

Merging #748 into master will increase coverage by 3.34%.
The diff coverage is 97.23%.

@@            Coverage Diff             @@
##           master     #748      +/-   ##
==========================================
+ Coverage   92.47%   95.82%   +3.34%     
==========================================
  Files         234      175      -59     
  Lines       10475     8064    -2411     
  Branches      944      728     -216     
==========================================
- Hits         9687     7727    -1960     
+ Misses        788      337     -451

Impacted Files	Coverage Δ
...metry-core/src/trace/instrumentation/BasePlugin.ts	81.57% <100%> (-5.27%)	⬇️
.../opentelemetry-plugin-ioredis/test/ioredis.test.ts	94.63% <100%> (ø)	⬆️
...ry-plugin-dns/test/functionals/dns-disable.test.ts	100% <100%> (ø)	⬆️
...lugin-https/test/functionals/https-disable.test.ts	100% <100%> (ø)	⬆️
...try-propagator-jaeger/src/JaegerHttpTraceFormat.ts	95.65% <100%> (ø)	⬆️
.../opentelemetry-plugin-pg-pool/test/pg-pool.test.ts	88.09% <100%> (ø)	⬆️
...lugin-https/test/functionals/https-package.test.ts	98.48% <100%> (ø)	⬆️
...ackages/opentelemetry-node/test/NodeTracer.test.ts	100% <100%> (ø)	⬆️
...try-plugin-dns/test/functionals/dns-enable.test.ts	100% <100%> (ø)	⬆️
...plugin-https/test/functionals/https-enable.test.ts	96.11% <100%> (ø)	⬆️
... and 103 more