Add Bitcoin Frost, Peercoin, and Solana images

updated theme zips and their hashes in theme.json except for chan and dark chan themes

chan.zip and dark_chan.zip updates omitted because of filesize limitations:
```
~/src/stack-theme-selector-server/data/themes$ git push
Enumerating objects: 29, done.
Counting objects: 100% (29/29), done.
Delta compression using up to 16 threads
Compressing objects: 100% (15/15), done.
Writing objects: 100% (15/15), 19.87 MiB | 1.03 MiB/s, done.
Total 15 (delta 11), reused 0 (delta 0)
remote: Resolving deltas: 100% (11/11), completed with 7 local objects.
remote: error: Trace: e1b22f30bb4537608d11904078c85aa7590f679e080f0a2ab566be57badd5837
remote: error: See https://gh.io/lfs for more information.
remote: error: File data/themes/dark_chan.zip is 108.89 MB; this exceeds GitHub's file size limit of 100.00 MB
remote: error: File data/themes/chan.zip is 109.07 MB; this exceeds GitHub's file size limit of 100.00 MB
remote: error: GH001: Large files detected. You may want to try Git Large File Storage - https://git-lfs.github.com.To github.com:cypherstack/stack-theme-selector-server
 ! [remote rejected] temp -> temp (pre-receive hook declined)
```

added images to each theme and their `theme.json`s

and ignored non-zip files in working theme data dir for QoL

.gitignore

@@ -1,3 +1,6 @@
 build
 node_modules
-.idea
+.idea
+
+data/themes/*
+!data/themes/*.zip

data/themes.json

@@ -11,8 +11,8 @@
         {
             "name": "Dark",
             "id": "dark",
-            "version": 6,
-            "sha256": "0fe23a086e85309912a50795aaa551e6786c3dd11554900c5238b84789770ec3",
+            "version": 7,
+            "sha256": "96aa68828ec397f91c5495005112a632b872a39dcb57cfcb09d4f122f25b1899",
             "size": "~680 kB",
             "previewImageUrl": "https://themes.stackwallet.com/previews/dark-theme.png"
         },
@@ -27,48 +27,48 @@
         {
             "name": "Forest",
             "id": "forest",
-            "version": 6,
-            "sha256": "8f94fcb8cecfaeebe9a4225155621a79451a91d9bfb4fc5e4edec920d08ac200",
+            "version": 7,
+            "sha256": "1aa6a8552d43d643ef34eb9c0d7e836f060543c13ee3f5b21aa664b963aa4752",
             "size": "~990 kB",
             "previewImageUrl": "https://themes.stackwallet.com/previews/forest-theme.png"
         },
         {
             "name": "Fruit Sorbet",
             "id": "fruit_sorbet",
-            "version": 6,
-            "sha256": "df706734f4d5f1ecdfd9fff696c0d31eea230a223faa1c566cb782ecbd10738e",
+            "version": 7,
+            "sha256": "3b25d37acf7e7130f2cd0801f1ea93cb2131188e575e09cb64b43f6a7d358f95",
             "size": "~780 kB",
             "previewImageUrl": "https://themes.stackwallet.com/previews/fruit-sorbet.png"
         },
         {
             "name": "Light",
             "id": "light",
-            "version": 7,
-            "sha256": "a00ebf22aede8b333d5db43e3a8febb792c36c7f84433c7e3ca5cb814bcc018c",
+            "version": 8,
+            "sha256": "2486f4fbd7a2ed959d64605188dcebc849178eedeb361896cb5a69bd0e3d05b9",
             "size": "~620 kB",
             "previewImageUrl": ""
         },
         {
             "name": "Ocean Breeze",
             "id": "ocean_breeze",
-            "version": 6,
-            "sha256": "e24500796b63bc741db868813cbc9567295e0b48ec4c8e0e5a25979891042e6a",
+            "version": 7,
+            "sha256": "4353a0a254a7afdefd3e08280fe030c0c7a525de61fa99233b369ab3ab6fa0ec",
             "size": "~3 MB",
             "previewImageUrl": "https://themes.stackwallet.com/previews/ocean-breeze.png"
         },
         {
             "name": "OLED Black",
             "id": "oled_black",
-            "version": 6,
-            "sha256": "4193623276150ab273905f15fcc9faf208db839ef89cbbdb7c591af04d64eac4",
+            "version": 7,
+            "sha256": "31192b8c2d4ca8b6f79780d70a503609dc7a9a0bdb6c59ff03a90ed44649b1e0",
             "size": "~690 kB",
             "previewImageUrl": "https://themes.stackwallet.com/previews/orange-dark-theme.png"
         },
         {
             "name": "Orange",
             "id": "orange",
-            "version": 6,
-            "sha256": "aa8b12f4e202958757b037481cac16454a9c1138af209502476c164b979efe0c",
+            "version": 7,
+            "sha256": "60ae83a4cc7dce2444a112308fe68601ec7661887f1ccb818c8f5a6cb2252e39",
             "size": "~180 kB",
             "previewImageUrl": "https://themes.stackwallet.com/previews/orange-theme.png"
         }