Bump version, and create changelog

CHANGELOG.md

+v2.3
+====
+
+* FEATURE: In the map categories menu, display next to each categorie how many elements are available for this category
+* FEATURE: Edit marker popup template
+* FEATURE: Ability to destroy my project
+* DOCS: Improve readability of admin interface text helpers
+* CODE: Architecture for DB migrations and Messages Changelogs
+* FEATURE: Webhooks availables !
+* BUG: Fix form builder labels and unique name edit
+* FEATURE: Form Image Field available (with url, not uploading)
+
+
+v2.2
+====
+
+* Creation of changelog
\ No newline at end of file

app/config/version.yml

 parameters:
-  app.version: 2.2.0
\ No newline at end of file
+  app.version: 2.3.0
\ No newline at end of file