Implement retry policy for the OTLP/gRPC exporter

[paivagustavo]

Closes #1632

• This was heavily inspired by the retry policy from the https://github.com/open-telemetry/opentelemetry-collector code.
• This uses the exponential backoff implemented by https://github.com/cenkalti/backoff.
• If this is accepted, it would be nice to unify this retry policy to the OTLP/HTTP exporter which implements a simpler retry policy.

[codecov]

Codecov Report

Merging #1832 (117e25a) into main (ec75390) will increase coverage by 0.0%.
The diff coverage is 88.6%.

@@          Coverage Diff          @@
##            main   #1832   +/-   ##
=====================================
  Coverage   78.6%   78.7%           
=====================================
  Files        137     137           
  Lines       7305    7373   +68     
=====================================
+ Hits        5749    5808   +59     
- Misses      1313    1321    +8     
- Partials     243     244    +1     

Impacted Files	Coverage Δ
exporters/otlp/otlpgrpc/connection.go	89.8% <85.0%> (-2.8%)	⬇️
exporters/otlp/internal/otlpconfig/options.go	91.0% <100.0%> (+0.2%)	⬆️
exporters/otlp/otlpgrpc/driver.go	92.4% <100.0%> (+0.4%)	⬆️
exporters/otlp/otlpgrpc/options.go	45.0% <100.0%> (+1.4%)	⬆️