Display local time in user's profile

📖 What does this MR do?

Related to #335459 (closed)

Displays local time in user's profile. Time zone can be set when editing your profile.

Note: If a user has not explicitly set their time zone it will default to the time zone set in the GitLab instance. This is because the timezone attribute defaults to Time.zone.tzinfo.name

💻 Local testing

1. Click your avatar in upper right corner and select Edit profile
2. Set your time zone
3. Navigate to your profile

📷 Screenshots

View	Before	After
Desktop
Mobile

🚦 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.