0031945: Foundation Classes - unique names of alerts of message report in DumpJson

0031945: Foundation Classes - unique names of alerts of message report in DumpJson

- add OCCT_DUMP_FIELD_VALUE_NUMERICAL_INC and OCCT_DUMP_FIELD_VALUES_DUMPED_INC - to increment key Value;
- add OCCT_DUMP_STREAM_VALUE_DUMPED - to give stream as a parameter of the DumpJson;
- correct Message_Report, Message_CompositeAlerts to increment keys;
- correct Message_AttributeMeter to have in result start and stop values united in value block: [start stop]. It's better for parsing;
- correct result of Message::MetricToString output for updated in 29451 Message_MetricType enum;
- correct Standard_Dump::AddValuesSeparator to avoid adding ',' in additional case;
- correct Standard_Dump::FormatJson to add opening/closing brace for the whole result (for valid parsing);
- correct Standard_Dump::FormatJson to ignore '\n' in value.