Repo standardization (MetaMask#5053)

* Repo standardization

- Adding GH actions workflow in place of circleci

- Adding CODEOWNERS file

- Adding basic .editorconfig file

- Adding basic .gitattributes file

- Specifying a minimum node version of 12

* PR Review Feedback

* Updating CODEOWNERS

* Adding 409H to CODEOWNERS

* Adding Node 10 to test versions

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true

.gitattributes

@@ -0,0 +1,3 @@
+* text=auto
+
+yarn.lock linguist-generated=false

.github/CODEOWNERS

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+# Lines starting with '#' are comments.
+# Each line is a file pattern followed by one or more owners.
+
+*                                    @MetaMask/devs @xrn @409H

.github/workflows/build-test.yml

@@ -0,0 +1,30 @@
+name: Build and Test
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+
+jobs:
+  build-test:
+    name: Build and Test
+    runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        node-version: [10.x, 12.x, 14.x, 16.x]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: yarn --frozen-lockfile
+    - run: yarn buildSample
+    - run: yarn ci
+  all-jobs-pass:
+    name: All jobs pass
+    runs-on: ubuntu-20.04
+    needs:
+      - build-test
+    steps:
+    - run: echo "Great success!"

.nvmrc

@@ -0,0 +1 @@
+v10