feat(instances): the Access tab splits the VM's screen from root's login

The tab put the console, a remote viewer address and two root forms at
one weight under "Access · Active · VNC", named buttons after their
implementation (VDI, Get console.vv), and repeated why the root forms
were disabled under each of them.

Now it has two sections. Screen: Open console with what it does, and
the remote viewer on a row of its own (address, Open, Download .vv
file). Log in as root: one line says how a password or key reaches the
guest now, written to the disk of a shut-off VM or sent through a
running VM's guest agent, or what to do when neither works; the
password and key rows follow with aligned labels. Ids, field names and
posts are unchanged.

static/css/webvirtcloud.css

@@ -129,6 +129,8 @@ th[aria-sort="ascending"]:not([data-sort-method="none"])::after {
     border: 2px solid var(--bs-border-color);
 }
 .power-dot.bg-success, .power-dot.bg-warning, .power-dot.bg-secondary { border-color: transparent; }
+/* the access tab's two login buttons line up */
+.access-act { min-width: 9rem; }
 
 /* the boot order: the devices the VM tries in turn, numbered and joined by a line */
 .boot-chain { counter-reset: boot; }