Modify script to support CLI arguments.

The usage should be analog to what is described [here](https://github.com/HiveMinds-EU/tw-install/issues/81). In essence:
running:
`productivity-install.sh`
should return the usage, like:
```
run `productivity-install.sh --choice` to manually select which elements you want to install and configure.
run `productivity-install.sh --language-tool` to automatically install language-tool
run `productivity-install.sh --latex` to automatically install latex
run `productivity-install.sh --gitlab ssh tor` to automatically install GitLab, set up your ssh and host it over tor.
etc.
```
Ps. I think arguments like `--gitlab ssh tor` might cause a problem, because it may expect only 1 space separated argument, so either `ssh` or `tor` so perhaps find a clever way to support passing multiple configuration parameters.

Similarly build an interface for the `productivity-uninstall.sh`

An example of how to set up such command line argument parsing can be found here for install:
https://github.com/Deployment-Oneliners/Self-host-GitLab-Server-and-Runner-CI/blob/master/install_gitlab.sh
and here for uninstall:
https://github.com/Deployment-Oneliners/Self-host-GitLab-Server-and-Runner-CI/blob/master/uninstall_gitlab.sh