Codechange: Add constants for original input/output cargo counts.

[PeterN]

Motivation / Problem

House, industry and industry tiles used to have 2 or 3 cargo slots, which was increased to 16 a long time ago.

However there are still many places that need to refer to the original 2 or 3 slot counts, due to compatibility with loading old savegames, NewGRF properties, or NewGRF callbacks.

These instances all use a hand craft 2 or 3.

Description

Add HOUSE_ORIGINAL_NUM_ACCEPTS, INDUSTRY_ORIGINAL_NUM_INPUTS and INDUSTRY_ORIGINAL_NUM_OUTPUTS and use them at relevant places that I can find.

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR touches english.txt or translations? Check the guidelines
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, game_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker