Add toolbar to native markdown editor

[newhinton]

Is your feature request related to a problem? Please describe.
It's an improvement for people who are not that fluent in in markdown syntax.

Describe the solution you'd like

Additional context
#785 (comment)
This is similar to the toolbar nextcloud/text provides

I already started working on this, PR' follows later.

Todo:

• Add missing/proper icons
• Make icon and text the same color
• handle "Unsaved/Saving/Saved/Last Modified"-State below original toolbars
• fix toolbar for mobile
• remove original threedot menu (or at least make it fit the new toolbar handling, exposing the most useful items)

In my trials i also centered the content properly. It is not anchored to the left sidebar anymore, so that the content stays centered. This is useful for wide screens

[newhinton]

This is how it looks like with proper icons. I am currently waiting for text#1996 so that we know if we can use all their icons. Most of them are from https://google.github.io/material-design-icons/ so we should be fine since it uses Apache 2 if we stick to that license

As to the new image upload/selection: I think with this toolbar we can easily do both.
The nextcloud-native selector gets a prominent icon in the toolbar, and upload-from-local is moved as an option to the overhang menu. that way we have both, but do not clutter the ui

[dodedodo]

I'd love to see a toolbar in the editor. But why not just use the nextcloud 'text' markdown editor as a whole?

nextcloud/text #884 has some more info on this. Nextcloud Collectives has already implemented text as its markdown editor.

[newhinton]

@dodedodo Because the "markdown-editor" the text app uses is deeply flawed. It reliably breaks markdown files and does not adhere to 'standards' and conventions. Until it stops beeing destructive it will probably not replace the one we use. I will link to the discussion later that explains the issue more deeply

Edit:

Here is the link to the discussion: nextcloud/text#593

[szaimen]

@dodedodo Because the "markdown-editor" the text app uses is deeply flawed. It reliably breaks markdown files and does not adhere to 'standards' and conventions. Until it stops beeing destructive it will probably not replace the one we use. I will link to the discussion later that explains the issue more deeply

Edit:

Here is the link to the discussion: nextcloud/text#593

This is now mostly resolved for NC25 IIRC