it compatible with the pgAdmin 4 color combination.
TODO::
Icons for the following nodes are in PNG format.
- Domain Constraint (Only the invalid icon)
- pgAgent Job Steps
- Green Plum database server
- Server (Only server.png, which is used in the create/edit dialog)
database server, shown in the preferences dialog.
Also, fixed the issue, when server type is not defined in the
DEFAULT_BINARY_PATHS, in the configuration.