Change "Code, test, and deploy together" message

Currently, when a user starts a new free GitLab.com account the welcome message is:

Welcome to Gitlab 
Code, test, and deploy together

We should update this message to be more celebratory congratulating them on creating an account and pitch the platform. We could also use similar messaging to the home page.

Welcome to Gitlab 
Faster releases. Better code. Less pain.

ICE score

Impact	Confidence	Effort	Score
2	4	1	2.33

Baseline improvement

This isn't an experiment but a small improvement