ESLint fixes and unified lint targets (#3424)

* optimise lint targets

* fix eslint config files

* fix app coverage settings

* tune eslint to warn about optional chains

nx.json

@@ -48,10 +48,17 @@
       ]
     },
     "lint": {
-      "inputs": [
-        "default",
-        "{workspaceRoot}/.eslintrc.json"
-      ]
+      "executor": "@angular-eslint/builder:lint",
+      "outputs": ["{options.outputFile}"],
+      "options": {
+        "lintFilePatterns": [
+          "{projectRoot}/**/*.ts",
+          "{projectRoot}/**/*.html"
+        ],
+        "cache": true,
+        "cacheLocation": ".eslintcache",
+        "ignorePath": ".eslintignore"
+      }
     },
     "e2e": {
       "inputs": [