Refactoring Datasource and DevTree code

[tristanlatr]

Describe
The Datasource and DevTree codebase have to be rewritten to:

• Fix DevTree search fails after adding a DataSource #78 and DataSources fails to instantiated from ID #79
• Unify the search() method across list-like objects of the library as described in the 0.3.4 release notes

SIEM and msiempy versions:

• msiempy: 0.3.4

Additional context
Add any other context about the problem here.

[tristanlatr]

Unify the search() method across list-like objects of the library as described in the 0.3.4 release notes

In order not to change the public API of the DevTree object, the search() method could return a Datasource object if there is only one result and a list of Datasources if there are more results.

It will still be confusing because the other objects will always return a list tho...

[tristanlatr]

The thing we should do here is to completely deprecate the use of DevTree object and create DataSourceManager, object with same interface BUT it should not overwrite the behaviour of the method search().
Of course the DevTree must stay around a couple of years with a deprecation notice.