[docs] Add missing import to "Installing and initializing the framework" guide

[munichpavel]

At commit 71c2a25042fbc1e87022657da8e14349b1ca93af of docs/basic/installing_and_initializing_framework.md, the first code snippet is missing TestFrameworkType in the import statement:

Is

rom data_factory_testing_framework import TestFramework
test_framework = TestFramework(
        framework_type=TestFrameworkType.DataFactory,
        root_folder_path='/factory',
    )

Should be

from data_factory_testing_framework import TestFramework, TestFrameworkType

test_framework = TestFramework(
        framework_type=TestFrameworkType.DataFactory,
        root_folder_path='/factory',
    )

[arjendev]

Hi @munichpavel,

Thanks for spotting and fixing this!