Non-interactively select language plugin for CI - #360

Issue #, if available: N/A

Description of changes: With CI that can run against different langauge versions, it will be more important to be able to accurately select the language version. The current approach of echoing the choice is a bit brittle.

$ cfn init --language "python37"
Initializing new project
What's the name of your resource type?
(Organization::Service::Resource)
>> AWS::Foo::Bar
Language plugin 'python37' selected non-interactively

This change also ensures plugin choice list is deterministically sorted and updates some Lambda runtimes.

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