Visualization Layer: Data Parsing Service

[kunkunzhu]

Changelogs

• Add content type field to Column Annotation object

---

Checklist:

• [x] Was this PR discussed in an issue? It is recommended to first discuss a new feature into a GitHub issue before opening a PR.
• [ ] Add tests to cover the fixed bug(s) or the newly introduced feature(s) (if appropriate).
• [ ] Update the API documentation if a new function is added, or an existing one is deleted.
• [ ] Write concise and explanatory changelogs above.
• [x] If possible, assign one of the following labels to the PR: feature, fix, chore, documentation or test (or ask a maintainer to do it for you).

---

discussion related to that PR

Issue #422