This is what we do everywhere else in our code base.

refs: #10684

Instead of seeing the site we're looking for we may have an "eepsite
unreachable" error page returned in the browser well before the timeout
is reached.

Previously I tried to check whether I2P is ready by looking for the
green star next to the Shared Client Tunnel entry. Unforunately,
however, Sikuli couldn't tell the difference between a green star and a
yellow one.

With recent versions of I2P, there are two shared client tunnel entries,
one for the old DSA encryption and one for modern edDSA. When *both*
entries are visible, I2P should be ready to use. This should be much
more reliable than checking whether port 4444 is open, especially since
the static sleep added to work around the upstream bug does not work
when the function is called from the shell library.

After lots of testing I've found that I2P will generally fail within 80
seconds if it's going to fail. Recently I discovered that sometimes,
however, it takes a bit longer. The page is still trying to load and we
press ESC, the browser may be at a stage in which the URL we were trying
to load will not be in the address bar. Pressing reload in this case
will be for naught.

After a fair amount of testing I have not seen it take longer than 120
seconds. This means that we should always be at a state in which
pressing reload will actually be able to reload the page.

I2P isn't started as quickly under systemd as it was with sysvinit.

This test requires an iso built within the branch from #10185 merged in.

…so they can also be used for the I2P Browser.

Note: Retrying will have to come in a future commit.

At the same time, rename the image file to match current
TestSuite-standards.

"Persistent" in the sense that it survives across scenarios. This is a
first step towards using a single Libvirt::Domain instance across the
full test suite run, which in turn is a step towards being able to use
Libvirt snapshots more easily (or at all, I think).

This was achieved with the following command:

    sed -i 's/@vm\>/$vm/g' -- features/step_definitions/*.rb \
                              features/support/*.rb \
                              features/support/helpers/*.rb

Just hovering a sub-menu (e.g. "Accessories") and waiting a bit is enough for
the submenu to open. But we did click on it, and if the sub-menu was already
open by hovering, then clicking closed it, of course resulting in FindFailed
exceptions to be thrown.