UI: New design for Add new user and Add new group

[pmolnar-dev]

• I have searched the issues of this repository and believe that this is not a duplicate.

Description 💡

• implement new designs for Add new user and Add new group according to figma design
• important, this issue should not be started until new design for Users is implemented

Link to designs:
https://www.figma.com/design/FkFkMYvnPPyXu4CSDbQG5o/TruBudget-%E2%AD%90%EF%B8%8F-%E2%80%93%C2%A0UI-Design-%26-DEV-Handoff?node-id=2898-179619&node-type=section&t=o2A5zDawUYkK1VCy-0