lib: add the `Ketrew_lsf` module (“long-running”)
test: add the `lsf` command to `cli.ml`
lib: confirm LSF job status with `bjobs`
lib: add function `State.kill`
test: add a nihup-setsid-job remmote murder
lib: add the `kill` sub-command to `Command_line`
lib: improve LSF update “policy”
lib: implement LSF killing
lib: add `--interactive` option to `kill`