'vehicle' class cleanup

[irwiss]

Summary

None

Purpose of change

Cleans various unused, rarely used, stubs and duplicate functions from vehicle class

Describe the solution

num_parts/num_true_parts/part_count needed special treatment;

• part_count(no_fake = false) - the default overload, returns parts.size() and is a duplicate of num_parts() except it uses fake_parts.size()
• part_count(no_fake = true) - iterated over 'parts' and counted all parts where is_fake is false
• num_true_parts() - returns parts.size() - fake_parts.size()

The problem is num_true_parts is used generic_vehicle_part_range which is in turn used inside vehicle::refresh() while fake_parts is being filled. Trying to use the actual real part count in the range class results in bike rack test failures, so to keep status quo and keep tests happy these were refactored to 3 functions:

• int part_count() const; - returns parts.size()
• int part_count_real() const; - uses std::count_if to iterate and count parts with with is_fake false
• int part_count_real_cached() const; - returns parts.size() - fake_parts.size() and used in the range class

I'm 90% sure generic_vehicle_part_range shouldn't be using fake_parts as it's being filled and it can cause issues, but it'll require a separate patch to figure out what's getting broken there

Unused:

• int break_off( int p, int dmg )
• void remove_owner()
• turret_data turret_query( const vehicle_part &pt ) const; - used once as a DIY const_cast hack, not actually needed
• turret_data turret_query( const tripoint &pos ) const;
• const vehicle_part &cpart( int part_num ) const; - no uses, no implementation, part() has const overload
• void force_erase_part( int part_num );
• bool valid_part( int part_num ) const; - no implementation
• bool has_any_parts() const; - unused
• int removed_part_count = 0; // NOLINT(cata-serialize) - unused variable, only written to

Useless:

• tripoint get_abs_diff( const tripoint &one, const tripoint &two ) const; - same as (one-two).abs() with extra steps

Rarely used:

• int num_fake_parts() const; - only used in tests, moved to the test
• int num_active_fake_parts() const; - only used in tests, moved to the test
• int num_true_parts() const; - renamed to part_count_real() to match part_count()
• void refresh_mass() const; - stub immediately calling calc_mass_center( true );

Duplicates:

• int num_parts() const; - duplicate of part_count(), replaced with part_count as that one had more users

Removed overloads:

• int part_count( bool no_fake = false ) const; only had 1 user with no_fake == true, split to no-parameter part_count() and part_count_real() (deduplicated and renamed from num_true_parts())
• std::vector<vehicle_part *> lights( bool active = false ); - all users had set active = true, removed the parameter, only returns enabled lights

Misc:

• bool real_or_active_fake_part( int part_num ) const; - was moved to vehicle_part, a few checks that actually checked this but didn't use the function weer made to use the function instead
• A test was also adjusted to use CAPTURE(...)s instead of std::cout prints

Describe alternatives you've considered

Testing

Compiler and tests should hopefully catch me

Additional context