`ogma-cli`: Re-structure README around backends. Refs #75.

[ivanperez-keera]

Re-structure README around backends, as prescribed in the solution proposed for #75.

[ivanperez-keera]

Change Manager: Verified that:

• Solution is implemented:

  • [X] The code proposed compiles and passes all tests. Details: Docker image:

    
    FROM ubuntu:trusty

  RUN apt-get update

  RUN apt-get install --yes software-properties-common RUN add-apt-repository ppa:hvr/ghc RUN apt-get update

  RUN apt-get install --yes ghc-8.6.5 cabal-install-2.4 RUN apt-get install --yes libz-dev

  ENV PATH=/opt/ghc/8.6.5/bin:/opt/cabal/2.4/bin:$PWD/.cabal-sandbox/bin:$PATH

  RUN cabal update RUN cabal v1-sandbox init RUN cabal v1-install alex happy RUN apt-get install --yes git

  We install the application first and then test it, in case any tests need to

  run the tool.

  CMD git clone $REPO && \ cd $NAME && \ git checkout $COMMIT && \ cd .. && \ cabal v1-install $NAME/$PAT/ --enable-tests && \ cabal v1-install $NAME/$PAT/ --enable-tests --run-tests -j1

  Command:
  ```sh
  $ docker run -e "REPO=https://github.com/ivanperez-keera/ogma" -e "NAME=ogma" -e PAT="ogma-" -e "COMMIT=41ef5b5f31fe4be8de06b4b2c8935eb10e0f1c01" -it ogma-test

  • [X] The solution proposed fixes the issues described. The change is to the README, so the solution is checked by visual inspection. The README is not focused on the targets and functionalities provided by Ogma.
• [X] Implementation is documented. Details: The update is to to the documentation.
• [X] Change history is clear.
• [X] Commit messages are clear.
• [X] Changelogs are updated.
• [X] Examples are updated. Details: No examples affected.
• [X] Required version bumps are evaluated. Details: No bump needed; bump executed.