Added `exchange` filter in `stocks\search`

[dot-agi]

Description

• [x] Issue Fixed: #4778
• [x] Summary of fixes/additions:

• Modified the argument exchange to the exchange_country argument and -e to -ec
• Added the new exchange filter that can search based on the exchange name e.g. NYS, FRA etc
• Fixed docstring for call_search in stocks_helper.py by adding info about exchange and industry_group arguments

How has this been tested?

Tested using various command argument combinations on the terminal and via SDK.

• [x] Make sure affected commands still run in terminal
• [x] Ensure the SDK still works
• [x] Check any related reports

Checklist:

• [x] I have adhered to the GitFlow naming convention and my branch name is in the format of feature/feature-name or hotfix/hotfix-name.
• [x] Update our documentation following these guidelines. Update any user guides that are affected by the changes.
• [x] Update our tests following these guidelines.
• [x] Make sure you are following our CONTRIBUTING guidelines.
• [x] If a feature was added make sure to add it to the corresponding integration test script.

Others

• [x] I have performed a self-review of my own code.
• [x] I have commented my code, particularly in hard-to-understand areas.