[skip-changelog] Migrate tests from test_config.py to config_test.go (#1898)

* Migrate TestInit from test_config.py to config_test.go

* Migrate TestInitWithExistingCustomConfig from test_config.py to config_test.go

* Migrate TestInitOverwriteExistingCustomFile from test_config.py to config_test.go

* Migrate TestInitDestAbsolutePath from test_config.py to config_test.go

* Migrate TestInitDestRelativePath from test_config.py to config_test.go

* Migrate TestInitDestFlagWithOverwriteFlag from test_config.py to config_test.go

* Migrate TestInitDestAndConfigFileFlags from test_config.py to config_test.go

* Migrate TestInitConfigFileFlagAbsolutePath from test_config.py to config_test.go

* Migrate TestInitConfigFileFlagWithOverwriteFlag from test_config.py to config_test.go

* Migrate TestDump from test_config.py to config_test.go

* Migrate TestDumpWithConfigFileFlag from test_config.py to config_test.go

* Migrate TestInitConfigFileFlagRelativePath from test_config.py to config_test.go

* Migrate TestAddRemoveSetDeleteOnUnexistingKey from test_config.py to config_test.go

* Migrate TestAddSingleArgument from test_config.py to config_test.go

* Migrate TestAddMultipleArguments from test_config.py to config_test.go

* Migrate TestAddOnUnsupportedKey from test_config.py to config_test.go

* Migrate TestRemoveSingleArgument from test_config.py to config_test.go

* Migrate TestRemoveMultipleArguments from test_config.py to config_test.go

* Migrate TestRemoveOnUnsupportedKey from test_config.py to config_test.go

* Migrate TestSetSliceWithSingleArgument from test_config.py to config_test.go

* Migrate TestSetSliceWithMultipleArguments from test_config.py to config_test.go

* Migrate TestSetStringWithSingleArgument from test_config.py to config_test.go

* Migrate TestSetStringWithMultipleArguments from test_config.py to config_test.go

* Migrate TestSetBoolWithSingleArgument from test_config.py to config_test.go

* Migrate TestSetBoolWithMultipleArguments from test_config.py to config_test.go

* Migrate TestDelete to config_test.go and delete config_test.py

Author: MatteoPologruto