Add ExtensionStore (from @polkadot/extension) (#142)

* Add ExtensionStore (from @polkadot/extension)

* Consistent naming, untested/unused File store

* Update File.ts

yarn.lock

@@ -1835,10 +1835,12 @@
     "@types/bs58" "^4.0.0"
     bs58 "^4.0.1"
 
-"@polkadot/ts@^0.1.58":
-  version "0.1.58"
-  resolved "https://registry.yarnpkg.com/@polkadot/ts/-/ts-0.1.58.tgz#bd8883d590fc5be27e1db75c5c629e6bc8c4ce5c"
-  integrity sha512-+veSrr59SefA43RX034eef1T8qhO15Ye0BQ1+3FxjuFBnlCVmzj6iKGuzCtp4kGp3uFeotQ3m/2xMA+akSwq4Q==
+"@polkadot/ts@^0.1.59":
+  version "0.1.59"
+  resolved "https://registry.yarnpkg.com/@polkadot/ts/-/ts-0.1.59.tgz#e7418db78ad50291a46d61a3ab34ab465c0c3bf0"
+  integrity sha512-+kiST4RjeuyMWu2HdqIA6Ph2AifjGvlQ5bLDe9mfuApH07h8fgtzu+xVE4FZvMkLtjyKD+FSbB/oVplq2R1WEw==
+  dependencies:
+    "@types/chrome" "^0.0.86"
 
 "@polkadot/types@^0.80.1":
   version "0.80.1"
@@ -1948,6 +1950,13 @@
   dependencies:
     "@types/base-x" "*"
 
+"@types/chrome@^0.0.86":
+  version "0.0.86"
+  resolved "https://registry.yarnpkg.com/@types/chrome/-/chrome-0.0.86.tgz#1026ef8e76db4fde1859cae858d73236fe670d69"
+  integrity sha512-7ehebPf/5IR64SYdD2Vig0q0oUCNbWMQ29kASlNJaHVVtA5/J/DnrxnYVPCID70o7LgHdYsav6I4/XdqAxjTLQ==
+  dependencies:
+    "@types/filesystem" "*"
+
 "@types/color-convert@*":
   version "1.9.0"
   resolved "https://registry.yarnpkg.com/@types/color-convert/-/color-convert-1.9.0.tgz#bfa8203e41e7c65471e9841d7e306a7cd8b5172d"
@@ -1977,6 +1986,18 @@
   resolved "https://registry.yarnpkg.com/@types/events/-/events-3.0.0.tgz#2862f3f58a9a7f7c3e78d79f130dd4d71c25c2a7"
   integrity sha512-EaObqwIvayI5a8dCzhFrjKzVwKLxjoG9T6Ppd5CEo07LRKfQ8Yokw54r5+Wq7FaBQ+yXRvQAYPrHwya1/UFt9g==
 
+"@types/filesystem@*":
+  version "0.0.29"
+  resolved "https://registry.yarnpkg.com/@types/filesystem/-/filesystem-0.0.29.tgz#ee3748eb5be140dcf980c3bd35f11aec5f7a3748"
+  integrity sha512-85/1KfRedmfPGsbK8YzeaQUyV1FQAvMPMTuWFQ5EkLd2w7szhNO96bk3Rh/SKmOfd9co2rCLf0Voy4o7ECBOvw==
+  dependencies:
+    "@types/filewriter" "*"
+
+"@types/filewriter@*":
+  version "0.0.28"
+  resolved "https://registry.yarnpkg.com/@types/filewriter/-/filewriter-0.0.28.tgz#c054e8af4d9dd75db4e63abc76f885168714d4b3"
+  integrity sha1-wFTor02d11205jq8dviFFocU1LM=
+
 "@types/fs-extra@^5.0.3":
   version "5.1.0"
   resolved "https://registry.yarnpkg.com/@types/fs-extra/-/fs-extra-5.1.0.tgz#2a325ef97901504a3828718c390d34b8426a10a1"
@@ -2052,6 +2073,13 @@
   resolved "https://registry.yarnpkg.com/@types/minimatch/-/minimatch-3.0.3.tgz#3dca0e3f33b200fc7d1139c0cd96c1268cadfd9d"
   integrity sha512-tHq6qdbT9U1IRSGf14CL0pUlULksvY9OZ+5eEgl1N7t+OA3tGvNpxJCzuKQlsNgCVwbAs670L1vcVQi8j9HjnA==
 
+"@types/mkdirp@^0.5.2":
+  version "0.5.2"
+  resolved "https://registry.yarnpkg.com/@types/mkdirp/-/mkdirp-0.5.2.tgz#503aacfe5cc2703d5484326b1b27efa67a339c1f"
+  integrity sha512-U5icWpv7YnZYGsN4/cmh3WD2onMY0aJIiTE6+51TwJCttdHvtCYmkBNOobHlXwrJRL0nkH9jH4kD+1FAdMN4Tg==
+  dependencies:
+    "@types/node" "*"
+
 "@types/node@*", "@types/node@^12.0.4":
   version "12.0.5"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-12.0.5.tgz#ac14404c33d1a789973c45379a67f7f7e58a01b9"
@@ -5378,6 +5406,11 @@ extend@~3.0.2:
   resolved "https://registry.yarnpkg.com/extend/-/extend-3.0.2.tgz#f8b1136b4071fbd8eb140aff858b1019ec2915fa"
   integrity sha512-fjquC59cD7CyW6urNXK0FBufkZcoiGG80wTuPujX590cB5Ttln20E2UB4S/WARVqhXffZl2LNgS+gQdPIIim/g==
 
+extensionizer@^1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/extensionizer/-/extensionizer-1.0.1.tgz#504544239a7610ba8404b15c1832091a37768d09"
+  integrity sha512-UES5CSOYqshNsWFrpORcQR47+ph6UvQK25mguD44IyeMemt40CG+LTZrH1PgpGUHX3w7ACtNQnmM0J+qEe8G0Q==
+
 external-editor@^3.0.3:
   version "3.0.3"
   resolved "https://registry.yarnpkg.com/external-editor/-/external-editor-3.0.3.tgz#5866db29a97826dbe4bf3afd24070ead9ea43a27"