[Zelda BOTW only] Improved change of savedata format

[pablopenna]

Changes

Changes in this commit are:

• Implemented clipboard for temporarily saving and loading the items
  data when changing endianess. This is because when endianess is changed,
  item data is corrupted. This clipboard is a workaround for that issue.
• Added general purpose functions to zelda-botw.js for getting and
  setting item data.
• Modifiers for weapons, bows and shields are now shown for new items
  created via the Savegame Editor.
• Other minor refactors (in save(), load(),...)

Testing

Tested locally (loading index.html) and once commit was pushed in https://pablopenna.github.io/savegame-editors/zelda-botw/

I successfully exported the savegame from my switch to Cemu.

Although I have only worked on items, some other player data is not corrupted and is exported just fine (e.g. Link's health, stamina or event flags).

Known Issues (when changing endianess)

• Player position is corrupted, so you will appear somewhere else bugged. This is easily solved by teleporting.
• Horse data is corrupted, you still have your horses but their name, appearance and statistics get corrupted. A workaround is remodifying their data via this same SaveEditor.

NOTES:

• I reused some pieces of code, hence duplicating some pieces of logic. I could have done a refactor but I tried to modify the original code the less possible.

• I recommend adding ?w=1 to the URL when checking the commit diff to ignore whitespace changes. My IDE removed trailing whitespaces from the files I touched.