Merge #1010

1010: Move the localization effort to Weblate r=mergify[bot] a=kaiyou

## What type of PR?

documentation

## What does this PR do?

This PR updates documentation for us to move the localization effort outside of POEditor. POEditor had archived our project and it was linked to my account. I suggest we move to a Weblate instance (hosted at TeDomum for the part I setup).

### Related issue(s)
- closes #916 

## Prerequistes
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [x] In case of feature or enhancement: documentation updated accordingly
- [x] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/guide.html#changelog) entry file.


Co-authored-by: kaiyou <pierre@jaury.eu>

docs/contributors/localization.rst

@@ -1,12 +1,12 @@
 I18N and L10N
 =============
 
-Using POEditor.com
-------------------
+Using Weblate
+-------------
 
-We are using integrations with POEditor.com for translating Mailu. If you would like to contribute to the localization process, feel free to ask us to add a language then you can contribute to translations.
+We are hosting our localization effort using Weblate.If you would like to contribute to the localization process, feel free to ask us to add a language then you can contribute to translations.
 
-The project : https://poeditor.com/join/project/VszspPuEpn
+The project : https://translate.tedomum.net/projects/mailu/admin/
 
 Using Poedit
 ------------

towncrier/newsframents/916.doc

@@ -0,0 +1 @@
+Move the localization effort to Weblate