md2html exercise generator

[juliaogris]

Next-up

• Fake backend with temporary Frontend question selection according to composition.
• Add group field to questions - only one question from group can be picked, txtars are auto-grouped.
• Update composition: one per group; Quiz, unittest question selection update: Round-robin from the different exercises to ensure all exercises are covered.

Clean-up

• Remove xmlns="http://www.w3.org/2000/svg" from inline svg
• Add width="200px" height="200px" to renderer.go for svg file output, remove for inline.
• Use ANSWER as part of question path, e.g. dot/{ANSWER}.evy
• Format all evy files, including inside txtar files
• Workout unittests and quizzes (question href/image rewriting)
• Don't validate question composition if there are sealed / ignoreSelaed questions.
• Build a server component for single-user
• Add JS for question selection and randomization

Done-up

• Add txtar file format
• Initial Fundamentals course content
• Deploy to learn.evy.dev static content only
• Prettier output from learn/content -> frontend/learn
• <title>evy · Question</title> => model.Name
• Remove <hr>
• Add table for composition to Exercise.
• Create unit Model; output model with unit badge box
• Create quiz Model
• Create unittest Model
• Create course Model; output model with unit badge boxes
• Track exercise and unit names (derive from h1 or add as frontmatter field)
• Finish catalog.json
• Re-arrange validateModelPaths to come after newModels
• Update validateModelPaths for: 1 course, 1 unit, 1 unittest, 1 exercise per dir.
• Fix cls command for buffer output
• Export (course) catalog
• Check learn/README.md
• Fix rsc.io/markdown replace

PRs:

• doc-site: Use shared spa and sidebar JS modules evy#391
• learn-site: Add SPA links, loading only page fragments evy#390
• deploy: Use special root path re-write for learn subdomain evy#389
• learn: Add sidebar to learn pages evy#388
• learn-site: Start building the foundation course evy#387
• learn-site: Prepare for initial learn-site generation evy#386
• learn: Prepare for txtar support by levy evy#385
• learn: Add support for text-based questions evy#384
• learn: Add verification field to question frontmatter evy#383
• learn: Add SubQuestions generated from question template evy#382
• cli: Support txtar format as input evy#381
• learn: Generate HTML with templates evy#380
• learn: Generate HTML with templates evy#379
• learn: Add course catalog exporting evy#378
• learn: Add unit, unittest, quiz and course model evy#377
• learn: Refactor question model and MD utilties evy#376
• learn: Add directory exporting evy#375
• learn: Update and refactor naming evy#374
• learn: Refactor utilities in preparation for exercise evy#370

[juliaogris]

Suggested question format using txtar package:

---
type: question
difficulty: medium
answer-type: single-choice
generate-questions: a,b,c,d # ensure more than one
generate-questions: all
---

## Understanding sequence: `move`, `color`, `circle` commands

Which program generates the following output?

[question](dot/dot.textar "evy:svg")

Choose one correct answer:

- [answers](dot/dot.textar "evy:source")