Add log when catalog is loading

[angelozerr]

XML catalog configuration is a nightmare to detect the problem when it doesn't work. Problems can occurs from:

• catalog path configuration (file path is not valid)
• XML catalog file not valid as syntax XML
• XML catalag file content configuration

We could already support the 1 problem by logging catalog patch which is valid or not.

[angelozerr]

This issue was done in #206

If log is enable, you can see :

• when XML catalog path is OK:

Adding XML catalog './catalog.xml' with expand system id 'file:///C/vscode-xml-test/catalog.xml' and root URI 'file:///C/vscode-xml-test/'.

• when XML catalog path is bad :

Cannot add XML catalog './bad-catalog.xml' with expand system id 'file:///C/vscode-xml-test/bad-catalog.xml' and root URI 'file:///C/vscode-xml-test/'.