docs: new styling docs / advanced / embedded components

[sissbruecker]

Adds the "Advanced / Styling Embedded Components" article for the new styling docs.

Note

The PR targets a base branch for the new styling docs. That branch has the old styling docs removed and new articles are added gradually until the new section is ready. Cross-references between new articles will be filled in later, respective sections have been marked with TODOs.

[github-actions]

AI Language Review

"Styling Embedded Components" AsciiDoc:

1. In the phrase "instead of the usual way with [classname]@StyleSheet," consider rephrasing to clarify the intended message, as the current wording may confuse readers about the standard method being referenced.

2. Ensure all bracketed placeholders (e.g., <<{articles}/flow/integrations/embedding#,embedded>>) are correctly formatted for AsciiDoc. If "{articles}" is intended as a placeholder, consider providing context or revising for clarity.