Closes #5

How it works:

1. Grabs outline for all functions for all currently opened buffers
2. Generates embeddings for all the functions
3. Generates embedding from current code selection
4. Uses spatial cosine distance to find similar embeddings to code selection
5. Sends top x matched embeddings as part of the query to copilot in format:

query
File: `<filename1>`
```<filetype_for_filename1>
<embeddings_for_filename1>
```
File: `<filename2>`
```<filetype_for_filename2>
<embeddings_for_filename2>
```
etc

TODO:

• Embed all open buffers
• Embed current buffer
• Limit based on token count (wait for tiktoken lua)
• Add config options of what should be embedded

Example

Outline debugging (inside of CopilotChatDebugInfo):

Context selection