Extend and add more toolbar buttons

[HMarzban]

Now we have the primary buttons on the toolbar,
It would be nice to have more buttons like check marks or create a new heading etc.
To have more buttons, I suggest adding a horizontal scroll bar to the toolbar where the user can scroll left or right to access more buttons.
(We had this feature in the Etherpad version)

@edsaperia What's your opinion?

[edsaperia]

Maybe if each of these is one button we can fit them all:

• style (normal, h1, ...)
• Bold, Italic, Underline, Strikethough, highlight, clear formatting (maybe this can be a dropdown)
• ol, ul, checkbox (maybe this can be a dropdown)
• media
• link