No provision of any subsequent act relating to any such appointment, employment, promotion, or removal shall be construed as inconsistent herewith or with any provision of sections 197.455 and 197.46 unless and except only so far as expressly provided in such subsequent act that the provisions of these sections shall not be applicable or shall be superseded, modified, amended, or repealed. Every city charter provision hereafter adopted which is inconsistent herewith or with any provision of these sections shall be void to the extent of such inconsistency.