Configure will also test the container engine by trying to run the
selected SDK image.
This may make the first configure a bit slow, as it downloads the image,
but after that the SDK will be cached locally.
Debian-like distributions install AFDKO's executables into libexec and
provide an `afdko` helper to call them.
Python's pip installs the executables in bin.
Let's support both.
* Make it more flexible on the image name,
* Remove the image type support, only Docker is likely to be supported.
* Add target runtime name (scout / soldier), independent of the image.
In steamrt-bootstrap,sh
+ Used quotes to prevent word splitting SC2046
+ Used $() notation rather than legacy backtick SC2006
+ which is non-standard. 'command -v' is builtin SC2230
In configure.sh
+ Assigned to local variable separately to avoid masking return values SC2155
+ Used to quote to prevent glob matching SC2053
+ Used -z command rather than ! -n SC2236
+ Fixed SC2129 which would have a minor performance gain of avoiding constantly opening and closing the makefile.
