Remove inline styling from AppUI packages

[NancyMcCallB]

Use a strict CSP as our main method for mitigating XSS attacks. Part of this is prevention of inline styles
Content security policyContent Security Policy can significantly reduce the risk and impact of cross-site scripting attacks in modern browsers.

[raplemie]

@kckst8 Can you provide which part is causing problem with the rule ? React should already handle correctly the style props by assigning them directly according to facebook/react#5878 (comment), so I suppose it is not what is causing issues (like resizing a panel or moving a floating widget around)

[raplemie]

After internal discussions with @kckst8, there is not current issue direclty with AppUI packages infringing no-style CSP, so I'll close this and we can create other issues if specific components turns out to be problematic.