[CO-386] Separate and expose wallet actions

[KtorZ]

Description

The action exposed there are necessary for someone who wants to start a
wallet node from haskell (like in the integration-tests for instance ... ). They're currently part of the server/Main.hs
which is an executable, making it impossible to be imported by another
module. This commits extract them from 'server/Main.hs' making them
easy to re-use and/or remove!

Linked issue

[CO-386]

Type of change

• 🐞 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)
• 🏭 Refactoring that does not change existing functionality but does improve things like code readability, structure etc
• 🔨 New or improved tests for existing code
• ⛑ git-flow chore (backport, hotfix, etc)

Developer checklist

• I have read the style guide document, and my code follows the code style of this project.
• If my code deals with exceptions, it follows the guidelines.
• I have updated any documentation accordingly, if needed. Documentation changes can be reflected in opening a PR on cardanodocs.com, amending the inline Haddock comments, any relevant README file or one of the document listed in the docs directory.
• [ ] CHANGELOG entry has been added and is linked to the correct PR on GitHub.

Testing checklist

• [ ] I have added tests to cover my changes.
• All new and existing tests passed.

QA Steps

Screenshots (if available)

[adinapoli-iohk]

LGTM, this is literally just code reshuffling.

[KtorZ]

Wallet integration tests still fail because tests are broken (currently being worked on). However, the wallet can still start correctly as expected. So merging this.