Multiple layout changes

[QNetITQ]

Tracking upcoming changes.

Vertical Tabs / Tab Groups / Pinned Tabs / Split View

Use one universal pinned tabs container rather than separate logic for vertical and horizontal (WaveFox v1.8.141)

[QNetITQ]

Need to change everything related to #titlebar in WaveFox v1.7.133.

https://bugzilla.mozilla.org/show_bug.cgi?id=1899598

[QNetITQ]

[tabsintitlebar] > [customtitlebar] (WaveFox v1.8.135)

https://bugzilla.mozilla.org/show_bug.cgi?id=1932600

[QNetITQ]

Implement the full mute button spec (WaveFox v1.8.136)

https://bugzilla.mozilla.org/show_bug.cgi?id=1921060

[QNetITQ]

Add support for string or char pref in stylesheets (v1.8.137)

https://bugzilla.mozilla.org/show_bug.cgi?id=1946764

[QNetITQ]

Tab animations for userChrome.css (Request)

https://bugzilla.mozilla.org/show_bug.cgi?id=1989829