Replace deprecated plugins during installation

[CodeShakingSheep]

Problem

• Fix #118

Solution

Do two replacements:

• Replace GitHub Organization Folder Plugin with GitHub Branch Source
• Replace Pipeline: Deprecated Groovy Libraries with Pipeline Groovy Lib

PR Status

• [x] Code finished and ready to be reviewed/tested
• [ ] The fix/enhancement were manually tested (if applicable)

Automatic tests

Automatic tests can be triggered on https://ci-apps-dev.yunohost.org/ after creating the PR, by commenting "!testme", "!gogogadgetoci" or "By the power of systemd, I invoke The Great App CI to test this Pull Request!". (N.B. : for this to work you need to be a member of the Yunohost-Apps organization)

[CodeShakingSheep]

!testme

[yalh76]

In the files changed, I don't see:

• Replace Pipeline: Deprecated Groovy Libraries with Pipeline Groovy Lib

Is it normal ?

[yalh76]

!testme

[yunohost-bot]

Alrighty!

[CodeShakingSheep]

In the files changed, I don't see:

• Replace Pipeline: Deprecated Groovy Libraries with Pipeline Groovy Lib

Is it normal ?

Yes because Pipeline Depreated Groovy Libraries is a dependency of the deprecated GitHub plugin. So, replacing the deprecated GitHub plugin replaces both deprecated plugins. Also see GitHub Organization Plugin dependencies.