Rename NginxUpload helper to FakeNginxReverseProxy

[#72354980]

Signed-off-by: Joseph Palermo <jpalermo@pivotallabs.com>
Extract FakeApp object used for "app" in specs

[#72354980]

Signed-off-by: Joseph Palermo <jpalermo@pivotallabs.com>
Make creation_opts more clear and move it closer to where it is used

[#72354980]

Signed-off-by: Joseph Palermo <jpalermo@pivotallabs.com>
Rename shared example modules

To make their purpose (contain shared examples) more obvious.

[#72354980]

Signed-off-by: Joseph Palermo <jpalermo@pivotallabs.com>