JVET-AF0122-SW: Lagrange multiplier optimization for ALF

This merge request is related to a RDO Optimization method in ALF, which was proposed in JVET-AF0122. Regarding the proposed method, the chroma Lagrange multiplier (including the scenes of chroma ALF and CCALF) will be adjusted by a scaling factor when the luma ALF APS transmission flag is ON and the number of history chroma ALF APS is insufficient. JVET-AF0122 was adopted to the next release of VTM, turned off by default for CTC.