(maint) Centralize dependency management in the gemspec

As per best practices, removed duplication between the Gemfile and gemspec.
There was also some seemingly superfluous install in the Gemfile.
Ordered the dependency by alphabetical order.
Tested locally by deleting the .bundle and recreating successfully

Gemfile

@@ -1,39 +1,6 @@
 source ENV['GEM_SOURCE'] || 'https://rubygems.org'
 
-gem 'json', '>= 1.8'
+gemspec
-gem 'pickup', '~> 0.0.11'
-gem 'puma', '~> 4.3'
-gem 'rack', '~> 2.2'
-gem 'rake', '~> 13.0'
-gem 'redis', '~> 4.1'
-gem 'rbvmomi', '~> 2.1'
-gem 'sinatra', '~> 2.0'
-gem 'prometheus-client', '~> 2.0'
-gem 'net-ldap', '~> 0.16'
-gem 'statsd-ruby', '~> 1.4.0', :require => 'statsd'
-gem 'connection_pool', '~> 2.2'
-gem 'nokogiri', '~> 1.10'
-gem 'spicy-proton', '~> 2.1'
-gem 'concurrent-ruby', '~> 1.1'
-
-group :development do
-  gem 'pry'
-end
-
-# Test deps
-group :test do
-  # required in order for the providers auto detect mechanism to work
-  gem 'vmpooler', path: './'
-  gem 'mock_redis', '>= 0.17.0'
-  gem 'rack-test', '>= 0.6'
-  gem 'rspec', '>= 3.2'
-  gem 'simplecov', '>= 0.11.2'
-  gem 'yarjuf', '>= 2.0'
-  gem 'climate_control', '>= 0.2.0'
-  # Rubocop would be ok jruby but for now we only use it on
-  # MRI or Windows platforms
-  gem "rubocop", :platforms => [:ruby, :x64_mingw]
-end
 
 # Evaluate Gemfile.local if it exists
 if File.exists? "#{__FILE__}.local"

vmpooler.gemspec

@@ -17,21 +17,10 @@ Gem::Specification.new do |s|
   s.bindir        = 'bin'
   s.executables   = 'vmpooler'
   s.require_paths = ["lib"]
-  s.add_dependency 'pickup', '~> 0.0.11'
-  s.add_dependency 'puma', '~> 4.3'
-  s.add_dependency 'rack', '~> 2.2'
-  s.add_dependency 'rake', '~> 13.0'
-  s.add_dependency 'redis', '~> 4.1'
-  s.add_dependency 'rbvmomi', '>= 2.1', '< 4.0'
-  s.add_dependency 'sinatra', '~> 2.0'
-  s.add_dependency 'prometheus-client', '~> 2.0'
-  s.add_dependency 'net-ldap', '~> 0.16'
-  s.add_dependency 'statsd-ruby', '~> 1.4'
-  s.add_dependency 'connection_pool', '~> 2.2'
   s.add_dependency 'concurrent-ruby', '~> 1.1'
+  s.add_dependency 'connection_pool', '~> 2.2'
+  s.add_dependency 'net-ldap', '~> 0.16'
   s.add_dependency 'nokogiri', '~> 1.10'
-  s.add_dependency 'spicy-proton', '~> 2.1'
-
   s.add_dependency 'opentelemetry-api', '~> 0.6.0'
   s.add_dependency 'opentelemetry-exporter-jaeger', '~> 0.6.0'
   s.add_dependency 'opentelemetry-instrumentation-concurrent_ruby', '~> 0.6.0'
@@ -39,4 +28,24 @@ Gem::Specification.new do |s|
   s.add_dependency 'opentelemetry-instrumentation-sinatra', '~> 0.6.0'
   s.add_dependency 'opentelemetry-resource_detectors', '~> 0.6.0'
   s.add_dependency 'opentelemetry-sdk', '~> 0.6.0'
+  s.add_dependency 'pickup', '~> 0.0.11'
+  s.add_dependency 'prometheus-client', '~> 2.0'
+  s.add_dependency 'puma', '~> 4.3'
+  s.add_dependency 'rack', '~> 2.2'
+  s.add_dependency 'rake', '~> 13.0'
+  s.add_dependency 'rbvmomi', '>= 2.1', '< 4.0'
+  s.add_dependency 'redis', '~> 4.1'
+  s.add_dependency 'sinatra', '~> 2.0'
+  s.add_dependency 'spicy-proton', '~> 2.1'
+  s.add_dependency 'statsd-ruby', '~> 1.4'
+
+  # Testing dependencies
+  s.add_development_dependency 'climate_control', '>= 0.2.0'
+  s.add_development_dependency 'mock_redis', '>= 0.17.0'
+  s.add_development_dependency 'pry'
+  s.add_development_dependency 'rack-test', '>= 0.6'
+  s.add_development_dependency 'rspec', '>= 3.2'
+  s.add_development_dependency 'rubocop'
+  s.add_development_dependency 'simplecov', '>= 0.11.2'
+  s.add_development_dependency 'yarjuf', '>= 2.0'
 end