Label text style support lineOverflow and ellipsis

[susiwen8]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

Add lineOverflow and ellipsis for label, also fix lineOverflow doesn't affect in title

Fixed issues

Close #15395

Details

Before: What was the problem?

After: How is it fixed in this PR?

Misc

• The API has been changed (apache/echarts-doc#xxx).
• This PR depends on ZRender changes (ecomfe/zrender#xxx).

Related test cases or examples to use the new APIs

NA.

Others

Merging options

• Please squash the commits into a single one when merge.

Other information

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[Ovilia]

I'm not sure if the default value should be 'truncate' since the document takes 'none' for default values. @pissang

[plainheart]

Just take this line of code, it's not to specify the default value but to define the type of lineOverflow.

[pissang]

I remember I didn't add ellipse and lineOverflow for some compatible considerations.

Especially the ellipse, treemap already has ellipse in the 4.x versions but with different meanings, which is same with overflow: 'truncate'. I noticed in this PR it is changed from boolean to string. In fact, it still works for the old code and will be converted to overflow: 'truncate'. Introducing ellipse to the label option will break it.

For lineOverflow it's mainly because I thought it is not implemented well yet.