CDB into o2cdb + namespaces + format function names

Importing STEER/CDB/ from AliRoot as starting point of the o2cdb,
applying naming conventions to it.
Get rid of cmake warning due to missing space in CMakeLists.txt

Apply clang format on o2cdb

Format function names.
The camelcase convention with lowercase starting letter has been
abandoned for compatibility with ROOT in the following cases:
GetName (for TObject derived)
Compare and IsSortable, for allowing TList,TClonesArray::Sort
XmlHandler::On* methods, for compatibility with TXMLParser

Remove hardcoded storage uris for DataType

First doxygen (Entry) and removing //______