[WIP] Change table to definition list in MetadataTable

[jwhitley]

This PR is a "proposal in code" that illustrates switching MetadataTable to use definition lists rather than tables. The current form is deliberately minimal to make absolutely clear what I'm proposing, but I wouldn't consider it complete. See below for possible additional work.

The benefits of using <dl> versus <table> include:

• Description lists' default styling works better in a narrow column like Kanban's lists. See screenshots below
• Can be styled exactly like table for backward compatibility
• Allows obsidian-kanban, themes, and user custom styles greater flexibility in changing the presentation of MetadataTable

Motivating use case: When I discovered this feature, I was already using Kanban for project notes with a Complete when:: metadata tag. But the use of tables forces a side-by-side presentation of each key/value pair, which was visually awkward for long keys (like this one) AND for long value text.

Here's a "before" image of the current codebase (v1.5.2) using <table>:

For comparison, here's how it looks with <dl>, but zero styling work:

If this seems like a good direction, likely next steps are:

• Fix the key styling, as the key's color: var(--text-muted) styling was dropped
• If strong backward compatibility is desired, restyle the description list to match the existing table
• (OPTIONAL) Add a simple switch to toggle between table-style (side by side) and dl-style (over-under) presentation
• (OPTIONAL) Add a style selector to let the user choose between multiple out-of-the-box styles
• Optimize the dl-style presentation specifically for Kanban's lists

Does this seem like a desirable approach? If so, what changes would you like to land this plugin?