Created badges documentation (#260)

Co-authored-by: Harmit Goswami <hgoswami@Harmits-MacBook-Pro.local>
Co-authored-by: Harmit Goswami <hgoswami@harmits-mbp.home>

Author: 3 people

src/assets/images/pontoon/profile/badges.png

@@ -58,6 +58,10 @@ This notification is sent once a day to authors of suggestions, to inform them t
 
 This notification is sent to team managers, as soon as a new user makes the first contribution to their team.
 
+### Badge awarded
+
+This notification is sent to a user upon being awarded with a [badge or new badge level](profile.md#achievement-badges) from reviewing and submitting translations, or promoting users.
+
 ### Manual notifications
 
 Administrators can send manual notifications to a project, including all locales or a subset of them. Unlike other types of notifications, this can’t be disabled.

src/tools/pontoon/notifications.md

@@ -5,11 +5,27 @@ The goal of the profile page in Pontoon is to provide a tool to showcase contrib
 The left column includes information about the user:
 * Profile picture and name.
 * Contact details.
+* Achievement badges.
 * Information on last known activity (when the user has submitted or reviewed a translation), last login in Pontoon, and the account’s creation date.
 * Roles in Pontoon (a user can have multiple roles across different locales).
 
 Users can customize their information and the visibility of specific fields in the [settings page](users.md#user-settings) (reachable using the `CHANGE SETTINGS` button).
 
+## Achievement badges
+
+Achievement badges awarded to a user are displayed beneath their contact information. The available badge types, from left to right in the image below, include:
+* **Translation Champion**, awarded for submitting translations.
+* **Review Master**, awarded for reviewing translations.
+* **Community Builder**, awarded for promoting users to higher roles.
+
+![Achievement badges](../../assets/images/pontoon/profile/badges.png "Screenshot of all possible achievement badges")
+
+Each badge has multiple levels. If a user holds a badge at level two or higher, the level is shown at the bottom left of the badge icon.
+
+Whenever they earn a new badge or level up an existing badge, users will be notified with a pop-up and a notification.
+
+## Activity graphs
+
 In the top central section there are two graphs:
 * **Approval rate** shows the ratio between the number of translations approved and the total number of translations reviewed, excluding self-approved translations.
 * **Self-approval rate** is only visible for users with translator rights, and shows the ratio between the number of translations submitted directly — or self-approved after submitting them as suggestions — and the total number of translations approved.