[spark-rapids] update for 2024/07 (#1204)

* [spark-rapids] update for 2024/07

* no reboots
* added dkms signing code
* added utility functions for checking OS
* cleaned up URL generation a bit
* using full path to bdconfig so that the script works from `sudo -i`
  prompt
* fixed error messages to indicate that secure boot with driver
  signing is available on 2.2
* cleaned up remove_old_backports
* clean apt cache before exit

* remove emacs temp file

* Some nits

* grammar correction maybe
* saying nvidia-smi a lot ; add existence check before running it
* remove upgrade_kernel function ; dataproc kernel version should never change.
* I meant oldoldstable, not oldstable

* DKMS packages sign with the wrong key, so installed key to the correct path

* Repaired Ubuntu18 installer

* reducing noise from credentials function
* removing mok symlink on ubuntu
* installing from .run file for ubuntu18

.gitignore

@@ -8,3 +8,6 @@
 # Ignore all bazel-* symlinks. There is no full list since this can change
 # based on the name of the directory bazel is cloned into.
 /bazel-*
+
+# Emacs
+*~