Split the constructor initializer use CLASS_COLON into CONSTR_COLON.

Keep all the options the same, so there is no change in test output.
Add options sp_after_constr_colon and sp_before_constr_colon

Assuming that indent_ctor_init_leading was only meant to apply to the
constructor colon, not the class declaration.
No tests fail, but that may be because there is no test coverage.
New options: indent_constr_colon, nl_constr_colon, nl_constr_init_args,
pos_constr_comma, pos_constr_colon

This should finish the split between the class initializer list and base
class list.
Update config files for the CLASS_COLON/CONSTR_COLON split
Mark stuff between a class base ':' and the '{' as IN_CLASS_BASE
There cannot be variables to align in a class base list
Add another class colon test