Migrate existing components to Composition API

[hidakatsuya]

This PR fixes a part of #18

手動でやるのが無理すぎたので、変換スクリプトで一括移行した。9割程度移行できていると思う。スクリプトは gist においてある。 https://gist.github.com/hidakatsuya/f1faf5753b6eddf9cf4bc4dae276f181

Steps

• [x] Bulk convert to Composition API by script
• [x] Fix lint, migrate unsupported, etc
  • [x] lint warnings
  • [x] src/components/ReportCanvas.vue
  • [x] src/components/ReportPane.vue
  • [x] src/components/SectionCanvas.vue
  • [x] src/components/toolbar/MenuDropdown.vue
  • [x] src/components/toolbar/ToolSelect.vue
  • [x] src/components/property/properties/base/TextProperty.vue
  • [x] src/components/property/properties/HorizontalAlignProperty.vue
  • [x] src/components/property/properties/OverflowProperty.vue
  • [x] src/components/property/properties/StrokeTypeProperty.vue
  • [x] src/components/property/properties/VerticalAlignProperty.vue
  • [x] src/components/property/properties/WordWrapProperty.vue
  • [x] src/components/items/TextItemBody.vue

[hidakatsuya]

一通りの動作を確認して問題ありませんでした。テスト通ったらマージします。