Add cloud credentials pCloud "hostname" field

We need new "hostname" field in pCloud cloud credentials, under "access token". Text input, not required.

Title: Hostname

Tooltip: Hostname to connect to.

Additionally, let's make sure that if OAuth URL returns non-existent field, we just ignore it. Now if I make pCloud URL our released FN/TN versions are using return "hostname" field, I get the following exception

ERROR TypeError: Cannot read property 'setValue' of undefined
at n (7.af7513507f2262d06c01.js:1)
at e.invokeTask (polyfills.48b12b61d94aa8c3a4d3.js:1)
at Object.onInvokeTask (main.730c7a3ccd6fbbf2dd74.js:1)
at e.invokeTask (polyfills.48b12b61d94aa8c3a4d3.js:1)
at t.runTask (polyfills.48b12b61d94aa8c3a4d3.js:1)
at t.invokeTask [as invoke] (polyfills.48b12b61d94aa8c3a4d3.js:1)
at p (polyfills.48b12b61d94aa8c3a4d3.js:1)
at h (polyfills.48b12b61d94aa8c3a4d3.js:1)

(so I had to change pCloud OAuth URL for newer releases)