Also removed unnecessary SVG files

This is needed for user-based PTS. Without write permission to
(in particular) the log folder, a PTS system ran from its specific user
cannot gain access to the scripts stored and copied under the pts user,
which is what the current PTS setup looks like.

Also updated the tar-ball and pushed it to OHWR, so the link to the
tar-ball has been changed in the README.

In addition, a link to the PTS tar-ball has been provided in the
readme file.

The freq_i input is now appropriately named per_i (for period), which is what
this input actually is.

Same as two commits back for the FM PTS.

As for the FM PTS, this avoid removing everything from the ubuntu/ folder (see a
couple of commits back for why we don't want this).

These changes make sure we completely overwrite the files we write. Otherwise,
with short ELMA crate hostnames and passwords, the rename script wrote the proper
values, but then left some characters from the previous files and these
characters could get in the way of running the shell or Python scripts.

This avoids inadvertently removing EVERYTHING inside the ubuntu/ folder
(including potentially other PTS's) on the test system.