Improve interface for string operations

Trim incoming string before converting to number
Remove use of std::strtod and std::stoi
Use std::string_view instead of std::string when possible

ApplicationLibCode/FileInterface/RifOpmCommonSummary.cpp

@@ -217,7 +217,7 @@ std::string RifOpmCommonEclipseSummary::unitName( const RifEclipseSummaryAddress
         }
     }
 
-    return RiaStdStringTools::trimString( nameString );
+    return std::string( RiaStdStringTools::trimString( nameString ) );
 }
 
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