[Feature] DND 3.0 compatibility

[PwQt]

As the name suggests - verify compatibility and if is not, then fix it.

If anyone reads this issue and finds any bug, please make a comment, i'll add it to main comment

Tested functionalities:

• Adding/removing spells from magic items works, the tab seems to behave correctly - as intended, since it wasn't changed by dnd5e 3.0
• Adjusted templates to work on the new sheet without breaking previous version compatibilities

Possible compatibility issues:

Currently found issues:

[PwQt]

Spells do not render, because of magicitemsheet.js

  async renderTemplate(name, cls, tab) {
    let template = await renderTemplate(`modules/${CONSTANTS.MODULE_ID}/templates/${name}.html`, this.actor);
    let el = this.html.find(`.${cls}`);
    if (el.length) {
      el.replaceWith(template);
    } else {
      this.html.find(`.${tab} .inventory-list`).append(template);
    }
  }

It seems like the .find method does not find correct element to append template.

[PwQt]

It seems like everything should be ready - i'll test it this weekend to check whether the release is possible, thanks to PR #52 and @voodoofrog

[PwQt]

Released with 1.6.0