Resolve "Add pronunciation to GitLab profile page"

What does this MR do?

For #25742 (closed)

This change

• Allows users to set their pronunciation from their profile (/-/profile page).
• The set pronunciation will then be shown in their public user profile (/:username page).

Screenshots or Screencasts (strongly suggested)

Adding pronunciation in user profile:

Pronunciation shown in user profile: Screen

Pronunciation shown in user profile: Mobile

DB Migrations

Up migration

rake db:migrate

== 20210729061526 AddPronunciationToUserDetails: migrating ====================
-- add_column(:user_details, :pronunciation, :text, {:null=>true})
   -> 0.0411s
== 20210729061526 AddPronunciationToUserDetails: migrated (0.0491s) ===========

== 20210729061556 AddTextLimitToUserDetailsPronunciation: migrating ===========
-- transaction_open?()
   -> 0.0000s
-- current_schema()
   -> 0.0003s
-- execute("ALTER TABLE user_details\nADD CONSTRAINT check_f932ed37db\nCHECK ( char_length(pronunciation) <= 255 )\nNOT VALID;\n")
   -> 0.0058s
-- current_schema()
   -> 0.0002s
-- execute("SET statement_timeout TO 0")
   -> 0.0006s
-- execute("ALTER TABLE user_details VALIDATE CONSTRAINT check_f932ed37db;")
   -> 0.0020s
-- execute("RESET ALL")
   -> 0.0007s
== 20210729061556 AddTextLimitToUserDetailsPronunciation: migrated (0.0189s) ==

Down migration

rake db:migrate:down VERSION=20210729061556

== 20210729061556 AddTextLimitToUserDetailsPronunciation: reverting ===========
-- execute("ALTER TABLE user_details\nDROP CONSTRAINT IF EXISTS check_f932ed37db\n")
   -> 0.0014s
== 20210729061556 AddTextLimitToUserDetailsPronunciation: reverted (0.0083s) ==

rake db:migrate:down VERSION=20210729061526

== 20210729061526 AddPronunciationToUserDetails: reverting ====================
-- remove_column(:user_details, :pronunciation)
   -> 0.0012s
== 20210729061526 AddPronunciationToUserDetails: reverted (0.0078s) ===========

How to setup and validate locally (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #25742 (closed)