Add authentication for haskell-servant

[7omb]

Adds support for API key, basic and bearer authentication in the OpenAPI specification. OAuth and multiple authentication schemes simultaneously are not implemented. The implementation uses servants generalized authentication.

If the OpenAPI specification does not specify an authentication mechanism it is compatible with the existing implementation. I added examples without authentication and for the different schemes here. The command:

./mvnw integration-test -f ./samples/server/petstore/haskell-servant/pom.xml

passes on my machine with BUILD SUCCESS.

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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[wing328]

Tests are good.

openapi-petstore> configure (lib)
Configuring openapi-petstore-0.1.0.0...
openapi-petstore> build (lib)
Preprocessing library for openapi-petstore-0.1.0.0..
Building library for openapi-petstore-0.1.0.0..
[1 of 2] Compiling OpenAPIPetstore.Types
[2 of 2] Compiling OpenAPIPetstore.API
openapi-petstore> copy/register
Installing library in /Users/williamcheng/Code/openapi-generator2/samples/server/petstore/haskell-servant/.stack-work/install/x86_64-osx/d7eaccd255e546d469fd16f5af3892ff7caa92ed8e070d4c3bfe612e97b830c4/9.0.2/lib/x86_64-osx-ghc-9.0.2/openapi-petstore-0.1.0.0-4YkDtr09w237nRoGp23ALC
Registering library for openapi-petstore-0.1.0.0..
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  01:15 min
[INFO] Finished at: 2022-05-26T23:43:31+08:00
[INFO] ------------------------------------------------------------------------

[7omb]

Thank you, that was quick!