Add templates for exercises batch 9

[meatball133]

Includes:

• Raindrops
• Resistor color
• Resistor color duo
• Resistor color trio
• Reverse string
• Rna transcription

[github-actions]

This PR touches files which potentially affect the outcome of the tests of an exercise. This will cause all students' solutions to affected exercises to be re-tested.

If this PR does not affect the result of the test (or, for example, adds an edge case that is not worth rerunning all tests for), please add the following to the merge-commit message which will stops student's tests from re-running. Please copy-paste to avoid typos.

[no important files changed]

For more information, refer to the documentation. If you are unsure whether to add the message or not, please ping @exercism/maintainers-admin in a comment. Thank you!

[kotp]

Trying to understand why the example files are changed here...

I thought this was about templates, and example files are not generally given by the upstream.

[meatball133]

problem spec added tests which were not coverd by the original example.

[kotp]

This should likely be a patch outside of this patch-set then.

Thanks for doing the work for the additional (breaking changes, I presume) functionality for the example.rb file though.