introduce Polar coordinate detector interface and Endcap ITKStrip detector
This MR introduces the ITkStrip detector as an example for the polar coordinate for endcap detector.
Currently this emphasis on the implementation for the ITkECStrip, so the PolarDetector has no generic implementation. If needed, there is a preliminary description
Since some calculations, e.g. residual or position of cluster are different in cartesian/polar coordinate, functions regarding these are defined in the detector class so that in Algorithm modules can keep common interfaces
In the naming of Polar/ITk detector, the getLocalPosition remains the same meaning of getting a point in local cartesian coordinate(defined by transfrom in geometry), the getLocalPolarPostion apples to get the polar position.
In the future, the ITkStrip detector will be moved to resource directory which aims to store user defined detectors