rx-html: Resolve naming conflicts between HTML and SVG attributes, e.g., style, title

[xerial]

In rx-html, SVG attributes often conflict with HTML attributes, which makes difficult to use both attrs together.

Ideally, both regular html and svg tags/attributes can be imported just by import wvlet.airframe.rx.html.all.*

Possible approaches:

• Instead of defining html and svg elements in separate files, detect namespace (html or svg) from the parent contest when rendering html or svg tags/attrs.
• Or just introduct non-conflict tag naming