[Feature, Prototype, Code] Word-wrap for the Axis Title #5700

There are already ongoing discussions about related topic:
#2053 and #382
First one stays open since 2017. Second - since 2016.

While we are waiting for the Unification of text rendering and wrapping, maybe it's worth to update convertToTspans() and buildSVGText() functions a bit, to have the text wrapping for the axes titles working.

Prototype solution

It needs improvements and some testing.
Proposed API:

layout.xaxis.title.wrap?: boolean
layout.yaxis.title.wrap?: boolean

If true - it's going to work like a word-break.
Default: undefined.

Here you are the code comparison: master...m-podlesny:master

Localhost test for a simple string:

str = 'Lorem Ipsum is simply dummy text of the printing and typesetting.';

ToDo: Improve the word wrapping if the string has <br />.

str = 'First line.<br />Second line that is very loooong.';
str = 'First line that is very loooong.<br />Second line.';

Let me know if it's worth to continue this way.