[feat] Create new UI tab for generating clusters and text summaries of clusters

[triathematician]

• [x] Ability to select chunks
• [x] Execute hierarchical clustering on selected chunks (filtered list only)
• [x] Parameters
  • [x] Maximum number of chunks
  • [x] Option to summarize
  • [x] Maximum number of tokens allowed for summarizing chunks
  • [x] Option for theme (and settings)
  • [x] Option for categories (and settings)
• [x] Pretty output
  • [x] Formatted html output
  • [ ] List output

[triathematician]

List output TBD in a later version