Support for Selenium nodes with Opera browser

[ehbello]

Description

This pull request provides the following changes:

1. Add the necessary files to build all types of Selenium nodes with the Opera browser.
2. Enable existing tests for the resulting Docker Images
3. Update the README.md file to describe the usage of the

Motivation and Context

These changes will allow us to use Opera as a new browser to test with Selenium.

We, at System73, have been using Selenium to test our software for several years. We needed to implement these changes for Selenium nodes to work with Opera and now we are sharing them with the community.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[claassistantio]

All committers have signed the CLA.

[diemol]

Thanks for this PR @ehbello!
I left a couple of suggestions, and also a comment because the standalone images are not being generated.

[ehbello]

I removed all automatically generated files (Dockerfile, README.md, etc) at release.

[maximehyh]

Hi @ehbello,
Thanks for all the work on the FF video support and Opera browser.
Since it is now Chromium based I was wondering if you or @diemol had some ambition to make the same with Edge (https://www.microsoftedgeinsider.com/fr-fr/download)?
Thx!
Maxime

[diemol]

This looks great @ehbello, thank you!
As mentioned before:

• We will merge this but we'll only have the first Opera images with the Selenium Grid 4 Alpha
• We will also monitor how much people use this image vs. how much maintenance demands.

[cben]

I removed all automatically generated files (Dockerfile, README.md, etc) at release.

FWIW, the other directories all include them in git.

• The READMEs are useful when navigating the github repo e.g. https://github.com/SeleniumHQ/docker-selenium/tree/master/NodeChrome

[ehbello]

@cben These files will be generated at release. Wait for it 😉