Information about tool images available from the added registries are retrieved only when needed

[janosmurai]

Type Of Change

• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Any modification in the test cases
• Any modification in the documentation

Checklist:

• I have read and followed the contribution guideline.
• I have checked to ensure there aren't other open Pull Requests for the same update/change.
• All the test cases pass and new modifications in the production code are 100% covered.
• I have made corresponding changes to the documentation.

Related Issue

Closing:
#202
DEM-283

Description

The list of tool images available from the registries is needed in the following cases:

• The user would like to create a new DevEnv. On the DevEnv Settings Window, the available tools should be listed.
• The user would like to modify a DevEnv. Again, the available tool images are needed on the DevEnv Settings Window.
• The user wants to list the tool images from the registries with the dem list-tools --reg command.

For the rest of the use cases where the registry information used to be loaded is now cleaned up, so DEM's overall speed increased.

This change allows the DevEnv installation to be executed even if there are tool images that should be pulled from registries not added to DEM.

How Has This Been Tested?

It was tested on Ubuntu 22.04, by trying out the commands.