docs(who-uses): add remberg

[cwoebker]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/nestjs/docs.nestjs.com/blob/master/CONTRIBUTING.md

PR Type

Adding a new company to the who uses documentation.
We use Nest.js at @rembergtech and are really happy.

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Docs
• Other... Please describe:

Does this PR introduce a breaking change?

• Yes
• No

Other information

[kamilmysliwiec]

For now, we decided to suspend adding more logos as there's a decent number of logos present there already and the page itself is getting bloated with images (we may even remove some of them in the near future). Instead, please consider adding yourself to the list below!