CI: Use `--psnr` arg for all `Enc Run` jobs

This makes it easier to check the PSNR before/after when there is a stat change.

Also, for All-Intra runs, encode 15 frames instead of 30 in accordance with CTC.
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a0a0b8d..c3a3a1d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -696,6 +696,7 @@
   extends: .enc-run-common
   variables:
     AOMENC_OUTPUT: all-intra
+    AOMENC_LIMIT: 15
   script:
     - ${AOMENC}
         --debug
@@ -753,6 +754,7 @@
         --end-usage=q
         --qp=${AOMENC_QP}
         --enable-keyframe-filtering=0
+        --psnr
         --obu
         --limit=${AOMENC_LIMIT}
         -o "${AOMENC_OUTPUT}.obu"
@@ -795,6 +797,7 @@
         --qp=${AOMENC_QP}
         --subgop-config-str=ld
         --enable-keyframe-filtering=0
+        --psnr
         --obu
         --limit=${AOMENC_LIMIT}
         -o "${AOMENC_OUTPUT}.obu"
@@ -848,6 +851,7 @@
 Dec Run (All-intra):
   extends: .dec-run-common
   variables:
+    AOMENC_LIMIT: 15  # Should match the same variable in 'Enc Run (All-intra)'
     AOMENC_OUTPUT: all-intra
     AOMDEC_OUTPUT: dec-all-intra
   needs: