Remove Admin Toolbar explicit dependency in composer.json file

Problem/Motivation

Onlyone module does not require admin_toolbar module as a dependency to work, however, it is declared as a dependency in the composer.json file.

It implies that admin_toolbar module is downloaded and included in the project codebase even if it is not required.

Admin Toolbar module is only required when the onlyone_admin_toolbar module is installed.

Steps to reproduce

* Install the onlyone module using composer.
* Confirm that admin_toolbar module is downloaded to the codebase and included in composer.lock file

Proposed resolution

Remove the explicit dependency on module's composer.json file

Remaining tasks

User interface changes

API changes

Data model changes