Add "list sites" function to the API

Add a function to the API to get a list of sites and with it’s status host.

Would be useful for this:

Hi Matthias,

this function is already existing in 1.6.
What is the problem in your case?

Output for “get_all_sites” looks like the following.
First Lines of Output formatted for readability

"result": {
    "sites": {
        "test2": {
            "url_prefix": "",
            "status_host": ("sitename", "hostname"),
            "multisiteurl": "",
            "user_sync": None,
            "socket": (
                    "tls": ("encrypted", {"verify": False}),
                    "address": ("", 6557),
            "alias": u"Site2",
            "user_login": True,
            "insecure": False,

Hatte ich dann wohl letzte Woche übersehen, danke.