[sm-144] Move SharedModule to root

[Hinton]

Type of change

- [ ] Bug fix
- [ ] New feature development
- [x] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [ ] Other

Objective

Part of the https://adr.bitwarden.com/decisions/0011-angular-folder-structure. Moves the SharedModule from modules directory to shared/shared.module.ts. The goal is to have each module in the application inherit this shared module which provides some common bootstrapping.

Before you submit

- [ ] I have checked for **linting** errors (`npm run lint`) (required)
- [ ] I have added **unit tests** where it makes sense to do so (encouraged but not required)
- [ ] This change requires a **documentation update** (notify the documentation team)
- [ ] This change has particular **deployment requirements** (notify the DevOps team)

[Hinton]

Superseded by #3225. Relevant commits have been cherry picked.