chore: Support customize server and socket options of undertow

[He-Pin]

Motivation: Add support for customized server and socket options of undertow Modification:

Modification: add serverOptions and socketOptions method.

Another option is define an def setup(builder:Builder):Unit = () method.

[lihaoyi]

Can you explain in the PR what those flags do?

[He-Pin]

Have dropped the old way, and added two methods for overriding.