fix(LeftSidebar): get rid of server styles for settings button

[ShGKme]

☑️ Resolves

• Settings button is a nix of global legacy server styles and @nextcloud/vue
  • It's style is a bit different from other buttons
  • It has double outline on focus
• Options 1: secondary - same as other similar apps - Mail, Calendar
• Options 2: tertiary - close to previous design
• Also, added a top padding

🖌️ UI Checklist

🖼️ Screenshots / Screencasts

🏚️ Before	🏡 After (secondary)	🏡 After (tertiary)
	.

🏁 Checklist

• 🌏 Tested with Chrome, Firefox and Safari or should not be risky to browser differences
• 🖥️ Tested with Desktop client or should not be risky for it
• 🖌️ Design was reviewed, approved or inspired by the design team
• ⛑️ Tests are included or not possible
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required

[Antreesy]

I'm fine with current state, as it draws much less attention (and looks better 😋 ):

Talk	Mail	Calendar

[nickvergessen]

Should this be handled in/via https://github.com/nextcloud-libraries/nextcloud-vue/blob/master/src/components/NcAppNavigationSettings/NcAppNavigationSettings.vue or a new component, to avoid all the custom code/handling in X apps?

[ShGKme]

Should this be handled in/via https://github.com/nextcloud-libraries/nextcloud-vue/blob/master/src/components/NcAppNavigationSettings/NcAppNavigationSettings.vue or a new component, to avoid all the custom code/handling in X apps?

I though about it but I'm not sure about it.

This cannot be handled via NcAppNavigationSettings (at least without making it a 2-in-1 component), because NcAppNavigationSettings is about "deprecated" collapsible settings, not a button.

This could be a new component, but its usage would probably have more variability than commons:

• In some apps, AppNavigation is fulfilled with navigation items and the settings button should look like a navigation item (Files, Photos)
• In some apps it would be secondary (Mail)
• In some apps it would be tertiary (Talk)

The only common is that it is a wide NcButton.

But we can discuss it with designers in @nextcloud/vue

[ShGKme]

I'm fine with current state, as it draws much less attention (and looks better 😋 ):

The current state - in main or in this PR (tertiary)?

[nickvergessen]

In some apps it would be secondary (Mail)
In some apps it would be tertiary (Talk)

This is exactly why I think it should be a common component.
I'm not sure the difference is intentional.

In fact I think that Talk, Calendar and Mail should look the same

[Antreesy]

The current state - ... this PR (tertiary)

As discussed above 🙈, Talk and Mail use simple NcButton as a trigger for opening a dialog, and Calendar has special component with "accordion" feature (<button> !!)

So I'd say, it would be better to summon design team here, to come to a conclusion on appearance for all three apps (but not the functionality), then apply resulting styles on Mail and Vue-lib for Calendar.

Another approach could be to add #trigger slot in NcAppSettingsDialog and keep styles consistent for both components on library level

[Antreesy]

cc @marcoambrosini

[marcoambrosini]

The accordion should go asap, in favor of the settings dialog with proper explanations.
I like both the secondary y and tertiary versions