Add a way to ignore files

[tmm1]

I tried clara on a couple projects and run into errors in the document loading process.

           Loading node_modules/ipaddr.js …                              
Traceback (most recent call last):                                                                                         
  File "/opt/homebrew/lib/python3.10/site-packages/langchain/document_loaders/text.py", line 40, in load
    with open(self.file_path, encoding=self.encoding) as f:                                                                
IsADirectoryError: [Errno 21] Is a directory: 'node_modules/ipaddr.js'
                                                                                                                                                                                             
  File "/opt/homebrew/lib/python3.10/site-packages/clara/cli.py", line 30, in setup   
    index.ingest()
  File "/opt/homebrew/lib/python3.10/site-packages/clara/index.py", line 73, in ingest 
    texts = self._get_texts()
  File "/opt/homebrew/lib/python3.10/site-packages/clara/index.py", line 53, in _get_texts
    documents.extend(loader.load_and_split())
  File "/opt/homebrew/lib/python3.10/site-packages/langchain/document_loaders/base.py", line 43, in load_and_split
    docs = self.load()
  File "/opt/homebrew/lib/python3.10/site-packages/langchain/document_loaders/text.py", line 56, in load
    raise RuntimeError(f"Error loading {self.file_path}") from e
RuntimeError: Error loading /Users/tmm1/fancybits/chrome-capture-for-channels/node_modules/ipaddr.js

           Loading ext/libhdhomerun/README.md …                           index.py:51
Traceback (most recent call last):
  File "/opt/homebrew/lib/python3.10/site-packages/langchain/document_loaders/text.py", line 41, in load
    text = f.read()
  File "/opt/homebrew/Cellar/python@3.10/3.10.12/Frameworks/Python.framework/Versions/3.10/lib/python3.10/codecs.py", line 322, in decode
    (result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa9 in position 10: invalid start byte

If there was a way to specify directories to ignore, I could tell it to stop traversing into directories like node_modules, vendor/gems and ext in these projects.