Support bash script access for the configuration settings

[technic960183]

Summary

Provide a bash script access for the configuration settings introduced in #383 .

Rationale

• Enables consistent and scriptable access to configuration setting values
• Simplifies Python-side logic
• Keeps behavior unchanged for existing tools (set_settings.sh)

Changes

Refactored Common Settings Utilities in set_settings.sh to settings.sh

Extracted key definitions and utility functions from set_settings.sh into a new file: tool/config/settings.sh
set_settings.sh updated to source settings.sh.

• Shared Variables: KEY_DESCRIPTIONS, VALID_KEYS, MAX_KEY_LENGTH
• Shared Utility functions: print_key(), show_valid_keys()

New Script: get_settings.sh

Added tool/config/get_settings.sh to retrieve a single key’s value from the settings.

Supports:

• --local, --global flags for scope control
• When neither is specified, try local first, then global.
• Output is machine-friendly (just the value), designed for use in other scripts or tools
• Also source settings.sh

Replaced Old Python Logic with the New Interface

Removed the old SystemSetting class in configure.py.

Added new function:

def get_setting(key, default_val=None)

Calls get_settings.sh directly and returns the setting value or default_val if not set.
Simplifies and unifies how Python retrieves config setting values using the same logic as the shell tools.

Tests

• set_settings.sh works the same as before.
• get_settings.sh could retrieve the values in the correct order.
• configure.py can read the default machine as before.