Add actual users name / email to dashboard welcome message

[dickeyy]

Is your feature request related to a problem? Please describe.
When the user goes to the dashboard, they should be welcomed by their name/email.

Describe the solution you'd like
When the user goes to /app, it should say "Welcome {user.firstName}" or "Welcome {user.emailAddresses[0].emailAddress}"

Describe alternatives you've considered
I mean, no welcome message I guess?

Additional context
I've implemented the fix for this already. I would like feedback before submitting a PR. here is what it looks like

[Erb3]

I feel like it should prioritize like following:

1. first name
2. if email includes a dot, use what comes before the dot (john.doe@example.com becomes john)
3. otherwise use everything before the @ (johndoe@example.com becomes johndoe)

[ixahmedxi]

Yeah I like @Erb3's idea here.

[MUK-Dev]

HI, is this issue up for grabs?

[dickeyy]

#375