[Elixir] Adding :package and :description to mix.exs template

[tobbbles]

Closes #9944

Adds additional values to mix.exs to enable publishing generated packges to Hex.

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
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  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
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[tobbbles]

cc @mrmstn

[mrmstn]

Hi @tobbbles, thank you very much for your PR!
Great to see that some generated clients will find their way to hex.pm.
Sadly I've no experience in publishing packages, but your changes look good to me so lets give it a shot 😁!

[aeneasr]

@tobbbles I couldn't find a way to set licenseId - do you know how we can set that value?

[aeneasr]

That was easy enough ... ory/sdk@20f602a