ogma-core: Move definitions related to ExprPair type to dedicated module. Refs #395.

[ivanperez-keera]

Move types and functions related to the type ExprPair from ogma-core:Command.Common to a new, internal, dedicated module, adjusting imports and uses as appropriate, as prescribed in the solution proposed for #395.

[ivanperez-keera]

Change Manager: Verified that:

• Solution is implemented:
  • The code proposed compiles and passes all tests. Details:
    • Build logs:
      • https://github.com/nasa/ogma/actions/runs/24461710806/job/71477459333
      • https://github.com/nasa/ogma/actions/runs/24461710798/job/71477458870
      • https://github.com/nasa/ogma/actions/runs/24461710707/job/71477458859
      • https://github.com/nasa/ogma/actions/runs/24461710683/job/71477458876
      • https://github.com/nasa/ogma/actions/runs/24461710781/job/71477458810
      • https://github.com/nasa/ogma/actions/runs/24461710692/job/71477459021
    • Build log archives:
      • logs_64751136773.zip
      • logs_64751136817.zip
      • logs_64751136847.zip
      • logs_64751136982.zip
      • logs_64751137013.zip
      • logs_64751137067.zip
  • The solution proposed produces the expected result. Details:
    The following Dockerfile checks that the function exprPair, and the types ExprPair and ExprPairT are not defined in ogma-core:Command.Common and are instead defined in Data.ExprPair, after which it prints the message "Success":

    FROM ubuntu:noble
    
    RUN apt-get update
    
    RUN apt-get install --yes git
    
    SHELL ["/bin/bash", "-c"]
    CMD git clone $REPO \
        && cd $NAME \
        && git checkout $COMMIT \
        && ! grep -nHre '^exprPair\>' ogma-core/src/Command/Common.hs \
        && ! grep -nHre '^data ExprPair\>' ogma-core/src/Command/Common.hs \
        && ! grep -nHre '^data ExprPairT\>' ogma-core/src/Command/Common.hs \
        && grep -qre '^exprPair\>' ogma-core/src/Data/ExprPair.hs \
        && grep -qre '^data ExprPair\>' ogma-core/src/Data/ExprPair.hs \
        && grep -qre '^data ExprPairT\>' ogma-core/src/Data/ExprPair.hs \
        && echo "Success"

    Command (substitute variables based on new path after merge):

    $ docker run -e REPO=https://github.com/ivanperez-keera/ogma -e NAME=ogma -e COMMIT=f79e4a3ca1b99a3dd9f2edf377975981c0a62d29 ogma-verify-395
    

• Implementation is documented. Details:
  The new module and the functions and types included in it are documented.
• Change history is clear.
• Commit messages are clear.
• Changelogs are updated.
• Examples are updated. Details:
  No updates needed; new code does not affect existing examples.
• Author is internal or has provided signed CLA.
• Required version bumps are evaluated. Details:
  Bump not needed; change is to internal modules and does not affect public API.