Add theme definitions table to Data Guides (#235)

* Add data theme definitions table to /guides

- Added `theme-definitions.json` with structured descriptions of all
  data themes (based on the [Definitions Proposal](https://lf-overturemaps.atlassian.net/wiki/spaces/PROJ/pages/353927169/Definitions+Proposal))
- Added `theme-definitions.mdx` page under /guides to display the themes
  table
- Introduced `ThemesTable` React component for rendering and styling the
  table

Note: Theme definitions are still incomplete and may contain errors.

* Update theme definitions

- Fix license name formatting
- Update address definition (GERSified, coverage, quality)
- Correct any fields transferred incorrectly from the wiki
- Render merging summary as list

* update theme definitions table structure, styles, and data

* clean up structure and links

* Fix fetch path for theme definitions JSON file

* update styles

---------

Co-authored-by: Dana Bauer <[email protected]>

Author: FlorianNachtigall

docs/guides/index.mdx

@@ -1,7 +1,19 @@
 ---
-title: Data Guides
+id: index
+slug: /guides/
+title: Guides
+sidebar_label: Overview
+description: Overture Maps data theme documentation
 ---
 
 import DocCardList from '@theme/DocCardList';
+import useBaseUrl from '@docusaurus/useBaseUrl';
 
-<DocCardList />
+
+
+
+## Data Theme Guides
+
+**<a href={useBaseUrl('/theme-definitions-table.html')} target="_blank">View Theme Definitions Table →</a>**
+
+<DocCardList />