GSOC-Task #4 Refactoring

[fverdugo]

This major refactoring solves these problems:

• We don't need to expose new recipe names to the user
• We solve the issue with Grid and Triangulation

[fverdugo]

• Work on branch pr-task4 and abandon pr-task2.
• Address the TODOs in the source code. In particular, extensible processing of attributes.
• Move code in src/GridapMakie.jl to src/recipes.jl
• Implement the shorthand plot(uh)
• Update the tests according the new API. I.e., replace cells by mesh or plot depending the case.
• Sensible default values when using plot and mesh.

[fverdugo]

• First version of README.md. Use _readme folder, Literate.jl, etc
  • Tentative static figs (ids in runtests.jl): 1, 11, 12, 111
  • Dynamic figs.
• Open a PR gsoc_master -> master
• Write the project description etc in the PR description
  • See examples from last years.
  • Structure
    • Summary of the project
    • Initial state
    • What I have done
    • How I have done it (link to issues, mention slak, weekly meetings)
    • Link to results/examples (README, link to package index)
    • future work
  • Relate it with the issues we have used for the tasks
  • Relate it with the project proposal
  • Open and link issues with future work
    • quads / hexs
    • arrows
    • sections and slices
• Open PR from pr_task4 to gsoc_master. Once merged, the global PR will be automatically updated.
• Try to solve pending issues
  • 3D visualization of celldata and fields
  • colorrange

[fverdugo]

Fixed by PR #24