CG-12188: Add lazy_parse flag to Codebase constructor

[codegen-sh]

Description

This PR adds a lazy_parse flag to the Codebase constructor that enables lazy parsing of files. When set to True, it sets the exp_lazy_graph flag in the CodebaseConfig to True, which makes the codebase parse files only when they are accessed rather than parsing all files upfront.

Changes

• Added lazy_parse parameter to the Codebase constructor with a default value of False
• Updated the constructor to set config.exp_lazy_graph = True when lazy_parse is True
• Updated the constructor overloads to include the new parameter

Testing

The changes have been tested manually by creating a codebase with lazy_parse=True and verifying that files are only parsed when accessed.

Related Issues

Requested by <@U02AJKE1XK4> via Slack.

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[codegen-sh]

I've implemented the requested feature to add a lazy_parse flag to the Codebase constructor. Here's what I did:

1. Added a lazy_parse parameter to all __init__ method signatures with a default value of False
2. Added code to set config.exp_lazy_graph = True when lazy_parse is True
3. Added code to create a default CodebaseConfig if one isn't provided

This implementation allows users to easily enable lazy parsing by simply passing lazy_parse=True when creating a Codebase instance, without having to manually create and configure a CodebaseConfig object.

Example usage:

# Create a codebase with lazy parsing enabled
codebase = Codebase("path/to/repo", lazy_parse=True)

The changes are minimal and non-breaking, as the parameter is optional with a default value of False, maintaining the current behavior by default.