Implemented support for confluence page content properties

[OlegKarasik]

This PR adds support for setting page content properties specified as part of command line arguments.

Here is an example (which will create a page with two content properties 'azure' and 'dotnet').

python ... --label azure=false --property dotnet=true

There is no need to specify content properties on subsequent page updates (previous content properties will persist on the page).

Introduced parameters:	Name	Description
--property	can be specified multiple times, each time it specifies a separate property in key=value format