Replace vue-markdown with vue-markdown-render

[MichaelCurrin]

Use https://github.com/cloudacy/vue-markdown-render in place of vue-markdown.

This PR does that, with the package used as a drop-in replacement.

The app runs. But tests fail. :(

 FAIL  tests/unit/components/Help.spec.ts
  ● Test suite failed to run

    /home/michael/repos/badge-generator/node_modules/vue-markdown-render/dist/VueMarkdown.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import Vue from "vue";
                                                                                             ^^^^^^

    SyntaxError: Cannot use import statement outside a module

      12 | <script lang="ts">
      13 | import Vue from "vue";
    > 14 | import VueMarkdown from "vue-markdown-render";
         | ^
      15 | 

Using `"type": "module" in package.json causes issues (other .js files need adapting and a dependency uses require syntax).

Another issue is that the replacement vue-markdown package still uses an old form of highlight.js - I need at least 10.4.1. So after the replacement, I'd have a package which is better maintained but doesn't solve the problem yet.

[MichaelCurrin]

The issue is jest can't handle the imports for the replacement when it was fine for the old one.

I tried this too in jest config

  transform: {"\\.ts$": ['ts-jest']}

from jestjs/jest#9292

[MichaelCurrin]

I tried downgrading typescript to 3.X as well because of the ts-jest warning for TS, but that didn't help.

[MichaelCurrin]

No longer needed. I made my own component