faq: add how to save KVS off for later `flux jobs` (or similar) perusal

[chu11]

may be a good one to add after user question

per @grondo answer

 grondo@corona212:~$ flux alloc -N1 --broker-opts=-Sstatedir=$(pwd)/test
f(s=1,d=1) grondo@corona189:~$ flux submit --cc=1-10 --wait --quiet hostname
f(s=1,d=1) grondo@corona189:~$ exit
exit
[detached: session exiting]
 grondo@corona212:~$ flux start --recovery=$(pwd)/test
Apr 08 08:33:29.430484 job-manager.notice[0]: Port range not specified in config with port-min and port-max. Using defaults of 11000 and 12000.
Apr 08 08:33:29.711729 sched-fluxion-resource.warning[0]: create_reader: allowlist unsupported
+-----------------------------------------------------
| Entering Flux recovery mode.
| All resources will be offline during recovery.
| Any rc1 failures noted above may result in
|  reduced functionality until manually corrected.
|
| broker.rc1_path    /etc/flux/rc1
| broker.rc3_path    /etc/flux/rc3
| config.path        -
| statedir           /g/g0/grondo/test
|
| Exit this shell when finished.
+-----------------------------------------------------
f(s=1,d=0) grondo@corona212:~$ flux jobs -a
       JOBID USER     NAME       ST NTASKS NNODES     TIME INFO
    fBASVTUj grondo   hostname   CD      1      1   0.063s corona189
    fBAR1UCQ grondo   hostname   CD      1      1   0.075s corona189
    fBAR1UCP grondo   hostname   CD      1      1   0.072s corona189
    fBAPXUv4 grondo   hostname   CD      1      1   0.072s corona189
    fBAPXUv3 grondo   hostname   CD      1      1   0.073s corona189
    fBAN3Vdi grondo   hostname   CD      1      1   0.073s corona189
    fBAK5X51 grondo   hostname   CD      1      1   0.081s corona189
    fBALZWMN grondo   hostname   CD      1      1   0.079s corona189
    fBALZWMM grondo   hostname   CD      1      1   0.079s corona189
    fBAN3Vdh grondo   hostname   CD      1      1   0.072s corona189