Rename all newBuilder() method to builder()

[mateuszrzeszutek]

Is your feature request related to a problem? Please describe.
I've noticed that the API & SDK uses the builder() name for the method that returns a new object builder. E.g. Attributes#builder(), Baggage#builder(), OpenTelemetrySdk#builder(). We should strive for consistency and do the same thing in all public APIs:

• Instrumenter#newBuilder() -> Instrumenter#builder()
• ...Tracing#newBuilder() -> ...Tracing#builder()

[iNikem]

Closed by #4407

[mateuszrzeszutek]

Unfortunately it's not done yet; the Instrumenter#newBuilder() method wasn't renamed

[MartinDai]

Unfortunately it's not done yet; the Instrumenter#newBuilder() method wasn't renamed

I found that there are many lines of code in this method that are not formatted, so I missed it when I modified it last time. I will resubmit a PR to fix it.

[mateuszrzeszutek]

Closed by #4475