Attack speed and move speed refacto/small stats refacto/mythic passives

[LinSun00]

• Attack speed per level is now correctly put into bonus stats.
• Attack speed and movement speed are now STAT_TOTAL_PROPERTY stats with getters adapted to their special functioning
• Distinction (again) between STAT_SUM_BASE_BONUS (set the stat as base + bonus) and STAT_STANDALONE (set the stat as bonus). Not sure this is necessary, but it made it clearer for me.
• New get_mythic_passive_stats method in BaseChampion. It is not in get_bonus_stats because heartsteel gives a percentage of the max health as bonus health. It is designed so that it works properly for current mythic passives, and so that it could work for new mythic passives with minor changes.
• Tests only for galeforce and everfrost. The tests are standardized with one mythic item + legendary items that should give enough diversity for robustness. TODO: test mythic passives for all other mythics Also: commits are misleading P.S. Au final c'était pas si dur à gérer que ça @PaulQbFeng

[PaulQbFeng]

Do we have to handle attack speed differently in Stats()when we do stat1 + stat2 ?

[LinSun00]

We don't have to handle attack speed differently in Stats(). The way it works is that items add stats to self.orig_bonus_stats.attack_speed. self.bonus_attack_speed is initialized with those item stats. Then the specifics of total attack_speed calculation are handled directly in the attack_speed getter