DTT2 - Testing module. Convert the track.yaml file into an object when the module starts

[mhamra]

Target version	Related issue	Related PR/dev branch
4.9.0	#5229 PR #5264	4495-dtt1-release

Description

Many classes of the testing module, such as the HostInformation and Executor classes, rely on the inventory.yaml file to get information. This implementation makes the code complex. Accessing an in-memory structure will simplify the code and improve performance and reliability.

I suggest:

• Implement an Inventory class that holds the information in the inventory.yaml.
• Validate the existence of the inventory.yaml and create the Inventory instance.
• All the functions that currently access the inventory file should be changed to access the Inventory instance.

Related PR comment: comment