Add witness TLS support

[kentbull]

Adds the same args from kli agent start to kli witness start.

If the base function createHttpServer is accepted into KERIpy then we can change my PR to KERIA to use that function rather than duplicate it.

This is missing a positive test for creating a tcp.ServerTls instance. I just need to figure out how to generate self-signed TLS certs on the fly or add a test set of TLS certs+key to the test fixtures.

[m00sey]

@kentbull generating certs could work, maybe someone like lets encrypt has a python lib.

Another option would be to use a mock library (like https://pypi.org/project/mockito/).

I'm happy to try put together a sample for you.

[kentbull]

Sam has a test in his iofo/hio library I'm going to bring over here: https://github.com/ioflo/hio/blob/master/tests/core/tcp/test_tcp.py#L657

[m00sey]

@kentbull you don't want to copy this test over, that would just mean we're retesting HIO in keripy.

You want to mock the tcp.ServerTls calls in keripy, as they're already tested in HIO

[m00sey]

You might be able to get away with just monkey patching the tcp lib for this test

[kentbull]

You might be able to get away with just monkey patching the tcp lib for this test

I did just that:

def test_createHttpServer(monkeypatch):
    port = 5632
    app = falcon.App()
    server = indirecting.createHttpServer(port, app)
    assert isinstance(server, http.Server)

    monkeypatch.setattr(hio.core.tcp, 'ServerTls', MockServerTls)
    monkeypatch.setattr(hio.core.http, 'Server', MockHttpServer)

    server = indirecting.createHttpServer(port, app, keypath='keypath', certpath='certpath', cafilepath='cafilepath')

    assert isinstance(server, MockHttpServer)
    assert isinstance(server.servant, MockServerTls)