Move OutputParserException to own file

[bendangelo]

Describe the bug
The exception is inside base.rb and rails will not be able to auto load it due the file name. Moving it to it's own file will allow the exception to be added to application_job.

Look here:

langchainrb/lib/langchain/output_parsers/base.rb

Line 32 in 41e232b

class OutputParserException < StandardError

To Reproduce
In a rails app:

class ApplicationJob < ActiveJob::Base
...
  retry_on Langchain::OutputParsers::OutputParserException, wait: 10.seconds, attempts: 3
...

end

Expected behavior
Loads the exception.

Terminal commands & output
Opening the rails console and typing: Langchain::OutputParsers::OutputParserException will fail.

Screenshots

Desktop (please complete the following information):

• OS: Linux
• Ruby version 3.4
• Langchain.rb version 0.19

[andreibondarev]

@bendangelo Would you be open to producing a PR for this?

[bendangelo]

Now isn't a great time for me but in the future I can.