implement 'list to sorted dict ' method

[sk-guritech]

# Input
[
    {"name" : "alice", "age" : 25},
    {"name" : "bob", "age" : 30},
    {"name" : "charlie", "age" : 35},
    {"name" : "david", "age" : 30}
]


ExtList(input, key="age")  # key is FunctionType | property | str | Hashable

#Output
{
    25 : [{"name" : "alice", "age" : 25}],
    30 : [{"name" : "bob", "age" : 30}, {"name" : "david", "age" : 30}],
    35 : [{"name" : "charlie", "age" : 35}]
}

[sk-guritech]

method name is group_by_key