Remove not-allowed currencies from the currencies dropdown in Setup

[r-martins]

Description

As reported on #13760 some deprecated currencies were being displayed in the setup process.
This PR removes these and other not-allowed currencies from the setup step 4 (customize your store).

Fixed Issues (if relevant)

1. Fixes Remove deprecated Brazilian currencies in the setup process #13760 by not displaying old and deprecated Brazilian currencies
2. Remove not-allowed currencies for being displayed

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-cicd2]

All committers have signed the CLA.

[r-martins]

#MLAU18

[okorshenko]

Hi @r-martins could you please sign CLA (Contributor License Agreement)?

[magento-engcom-team]

Hi @okorshenko, thank you for the review.
MAGETWO-88155 has been created to process this Pull Request

[r-martins]

Hi @okorshenko ,
I just signed the CLA and added the used e-mail to my account. ;)

[ihor-sviziev]

@r-martins @okobchenko is there any reason why new property was added with protected visibility instead of private?