GRUF-7: Add outer_around hook

Merge pull request bigcommerce#13 from splittingred/ARCH-309

ARCH-309: Add ability to specify a separate gRPC logger from the Gruf logger

Merge pull request bigcommerce#11 from splittingred/GRUF-1

GRUF-1: Add ability to run multiple around hooks

Fix issue with around hook

Version 0.11.4

Pass the service instance into hooks for reference

Ensure timer is measuring in milliseconds

Fix issue with interceptor and call signature

Merge pull request bigcommerce#5 from splittingred/ARCH-227

ARCH-227: Add instrumentation layer and registry

Merge pull request bigcommerce#3 from splittingred/ARCH-225

ARCH-225: Make endpoints auto-mount, rename to Gruf::Service