- update fuzz documentation
- revise the base64 decoder
- move ConfigManager into its own .cpp
- remove namespace httputil::header
- more specific error code
- RuntimeID rc_id_  -->  std::string client_id_
- TracerId  -->  TracerID
- remove disambiguating "template" keyword
- document k_apm_capabilities
- missed a spot when removing namespace httputil::header
- no need to optimize target file lookup
- slightly safer product parsing

- Update base64 implementation to not rely on little endian.
- Move ConfigUpdate in its own heade file