Add "Use exclude settings and ignore files" option in Search View

[sgraband]

Feature Description:

Add "Use exclude settings and ignore files" option in Search View

Currently, Theia's search view does not provide the option to toggle "Use exclude settings and ignore files" that is available in VS Code's search exclude box.

Current Behavior:

• In Theia, it appears that gitignore files (and potentially other ignore files) are always applied to search results, filtering out ignored files without giving users control over this behavior.

Requested Feature:

• Add a toggle option in the search view's exclude box to enable/disable "Use exclude settings and ignore files", matching VS Code's functionality.

Proposed Implementation Approach:
As a first step, it would be acceptable to:

1. Simply disable all current ignore/exclude filters in the Theia codebase with the toggle
2. Later improve and extend support for:
   • Exclude settings
   • Various ignore files (e.g., .gitignore, .ignore, etc.)

This would give users more control over their search results and align Theia's search capabilities more closely with VS Code.