Use Multiword Vue Component Names

[kkreine]

Closes #2463

What does this PR do?

This changes the Vue component names to be multi-word to abide by the new style guide --> https://vuejs.org/v2/style-guide/#Multi-word-component-names-essential

Running yarn lint showed 22 component names that needed to be changed to multi-word. I changed them to names that made sense to me, but I am happy to change them if requested.

Some changes to note: I was unsure what to change the Markdown component to, so I changed it to MarkdownRender. To make the Sidenav component multi-word, I would it and other occurrences of it to SideNav. Case insensitivity did not change the file names in git, so I can fix this if it is approved to change Sidenav to SideNav

Links to related issues

Checklist

• [X] added a test, or explain why one is not needed/possible: not needed
• [X] no unrelated changes
• [ ] asked someone for a code review
• [X] joined #karrot:matrix.org
• [X] added an entry to CHANGELOG.md (description, pull request link, username(s))
• [X] N/A - tried out on a mobile device (does everything work as expected on a smaller screen?)

[github-actions[bot]]

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