Early initialization of DEFAULT_STYLE

[zokrezyl]

Hi,

Was trying to use rich inside brython, but seems that their re matching of the colors (early init). While 99% of cases this is not causing problems, maybe would be a great idea to allow the init with custom theme and not depend on default theme.

I am planning to use it for headless logging and generate json based output that may be rendered later on terminal or somewhere else. In such use-cases custom theme would be also useful. In such situations I would make the evaluation of colors "lazy", and evaluate them only when really rendered to the terminal.

About rendering to json/yaml, will write another post here.

Regards
Z