Add zsh & PowerShell options for Code Builder terminal window

**Is your feature request related to a problem? Please describe.**
A clear and concise description of the problem. For example: I'm always frustrated when [...]

## Goal

I want parity between desktop VS Code and Code Builder terminal options so that I can easily move between them without having to setup/install or worse, re-write code.

- **MacOS**: Starting in 2019 (Catalina) MacOS switched from Bash as the default shell to `zsh`. I tried `apt-get install zsh` but it needs admin and `sudo` command isn't found
- **Windows**: Windows includes PowerShell by default and is an option in the terminal window. [Install PowerShell via apt-get](https://docs.microsoft.com/en-us/powershell/scripting/install/install-ubuntu?view=powershell-7.2#installation-via-package-repository)

**Describe what you are ultimately trying to do**
What is your use case, how might you do this today?

I have custom zsh scripts (I imagine Windows customers have custom PowerShell scripts) for common automation tasks that I want to use, including my profile `.zshrc` profile with command aliases.

Ex:

```
alias screenshot="chrome --headless --disable-gpu --screenshot"
alias html="chrome --headless --disable-gpu --dump-dom"
alias glog="git log --pretty=format:'%h - %an: %s' --graph"
```

```screenshot https://developer.salesforce.com``` - Auto-saves a screenshot of the web page
```html https://developer.salesforce.com``` - Writes html for headless chrome to standard output (or pipe/filter as needed)
```glog``` Shows a pretty view of git commits/branches to standard output

**Describe how you think Code Builder can help solve your problem or improve your work**
A clear and concise description of what you want to happen.

Seamless move from desktop to web

**Additional context**
Add any other context or screenshots about the feature request here.

Usa la issue #133 come punto di partenza per i requisiti: confronta le opzioni di terminale esistenti di Code Builder con VS Code desktop, quindi verifica come vengono gestiti la disponibilità di zsh e PowerShell e i profili come .zshrc. Il lavoro è completato quando Code Builder offre entrambe le opzioni di shell richieste e supporta i casi d’uso indicati per profili e script; nella issue non sono specificati file né test.

Scritto dal modello di indicizzazione a partire dal testo della issue.