Feature/global style option

[nicmosc]

Allow injectGlobal option of ThemeProvider/DrylusProvider to be disabled when using Drylus in a pre-existing, non-drylus app e.g. Marketplace.

This change makes it so that the styling of drylus-driven components/features is more isolated by making fonts relative to their closest font-setting parent (e.g. ThemeProvider when using the injectGlobal=false option).

If the option is not disabled, then styles are injected globally like before (in fully drylus apps), so nothing is affected visually.

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[Bartmr]

Just to confirm, this is a way to avoid styles from a parent app to cascade down to a frame of the screen using drylus right?

[nicmosc]

@Bartmr actually it's the opposite: The theme provider from drylus needs to add styling to the html and body elements of a website to make some properties global as that's the standard behaviour of most website. E.g. font-size is defined in the body of the website, and all children use relative values to define their font.
If you use rem (old one) you would base yourself solely on the property set on body, meaning that if the website set a different font size to what drylus is used to (e.g. Marketplace has a font-size of 15px), then things will look strange. Thus we decided to use em which uses the closest parent font-size, and defaults to the body one if that's the only component that sets it.
At the same time, since Theme provider had to set the font-size=14px on the website body, it would override the Marketplace one, which was 15px. Because of this, any of the non-drylus text on marketplace would look really tiny. By using the injectGlobal=false we don't set styles on the body from the Theme provider, meaning any code outside of this component will keep their original styles as the body was not affected

[Bartmr]

@nicmosc Got it. already clicked approve

[nicmosc]

@LeopoldArkham ☝️