Update preview screens (#267)

New preview screens for project manager and gem preview
---------

Signed-off-by: Pip Potter <[email protected]>

Gem/preview.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:6d6204c6730e5675791765ca194e9b1cbec282208e280507de830afc2805e5fa
-size 41127
+oid sha256:936e6057fd22a0c7ef6c48b66d7495dcab105052eaaf24d11b3baff8cce932dc
+size 29895

preview.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:682ecefceef4c154e386cd2dcdca2db7a3357c078777018968b181fd94abe7c8
-size 75685
+oid sha256:06e6db9ae8c332ef40921ede4ac1aa5637e9125cf616787d1640809ed8fc565a
+size 117744