fix: ADDON-66599 deprecate splunk-hec-token default value and break test execution on exception

[mkolasinski-splunk]

• deprecate default value of splunk-hec-token - give a warning when it's used
• add console handler to logger - warnings and errors beside being logged to pytest_splunk_addon.log are also logged to console
• other minor refactors from PR-803

References: https://splunk.atlassian.net/browse/ADDON-66599 https://github.com/splunk/pytest-splunk-addon/pull/803/files

[srv-rr-github-token]

:tada: This PR is included in version 5.2.1-beta.1 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: