Add normalmap support for node

[metalbracket]

Problem

Currently, when using node specular (? not sure about what it is), reflections on nodes are very flat, and don't look nice.

Here, see this picture of grass getting light on them.

It looks like the grass is made out of plastic.

Also, while I'm at it there are artifacts (correct name?)

Maybe my settings are not high enough for the artifacts to not be there.

Solutions

Add normalmaps (if the term is correct), to add more detail and not make it look so smooth.

Alternatives

Maybe some kind of grayscale image which tells how much reflection is on this part, remove it, or make it based on the texture

Additional context

No response

[metalbracket]

Note: You may need to look closely at the second image to see the brighter line.

[appgurueu]

Related to (effectively a sub-issue of) #8854. The artifact should probably be in a separate issue.