Let admins choose the default order of appearance of the initiatives

Is your feature request related to a problem? Please describe.
Currently the initiatives appear in a random order. In some cases the admins would like them to appear by the most recently published or the most commented, etc. As an admin, I would like to be able to choose the default order of appearance of the initiatives in the FE initiatives index. 

Describe the solution you'd like

The solution we would like to propose is to add a “Settings” tab in “admin/initiatives” secondary navbar so that admins would be able to :

• Short term: choose the default order of appearance of the initiatives in FE index.
• Add label : “Default order of appearance of the initiatives”
• Add dropdown list :

<select name="initiatives_order">

<option value="1" selected="selected">Random</option>

<option value="2">Most recent</option>

<option value="3">Most signed</option>

<option value="4">Most comented</option>

<option value="5">Most recently published</option>

</select>

• Medium/long term: set initiatives general configurations (like components enabled, default signature time period length, etc.

Additional context
A “Settings” tab was added in the same way for assemblies general settings in https://github.com/decidim/decidim/pull/6040

Does this issue could impact on users private data?
No

Funded by
Funded by département de Loire-Atlantique.