Simplify text shape
- Shape
   - [x] Only rich text (remove `richText` property)
   - [x] Convert plain text string to rich text doc nodes when loading ( in `convertToLatestVersion()`)
   - [x] Bring back word wrap
   - [x] Adjust underline offset
- Controller
   - [x] Allow to resize width of text shape
- React
   - [x] Remove `DGMPlainTextInplaceEditor`
   - [x] Rename `DGMRichTextInplaceEdutor` to `DGMTextInplaceEditor`.
