Merge branch 'nsw_clus_tools' into '21.3'

MM clusterization tool

See merge request atlas/athena!20256

(cherry picked from commit 4b8b9814)

8c08d44b Moving MM Clusterization to the example Clusterization tool
fafbf153 Adding clusterization tool configuration
59243ab0 Updating clusterization and configuration
dd82b2c5 Fixes in the clusterization algs and converters
f8b5f52f Fixes in the MM Cnv
0b77e073 Fixes
b5139923 Fixes