Fix several bugs

* increase performance of loading large model #77
* #78
* #69
* Enumeration values are not handled correctly
* For a structured value model, switching models leads to losing connections
* When editing entity, the text "Entity should be upper case" appears twice
* On List Characteristic user can choose a datatype or elementCharacteristic but not both
* Filter mode: Case when new connections are displayed after switching between models
* Data type doesn't change when you select another the Characteristic class

core/.eslintignore

@@ -0,0 +1 @@
+node_modules

core/.eslintrc.json

@@ -1,12 +1,12 @@
 {
   "root": true,
   "ignorePatterns": ["**/*"],
-  "plugins": ["@nrwl/nx"],
+  "plugins": ["@nx"],
   "overrides": [
     {
       "files": ["*.ts", "*.tsx", "*.js", "*.jsx"],
       "rules": {
-        "@nrwl/nx/enforce-module-boundaries": [
+        "@nx/enforce-module-boundaries": [
           "off",
           {
             "enforceBuildableLibDependency": true,
@@ -23,7 +23,7 @@
     },
     {
       "files": ["*.ts", "*.tsx"],
-      "extends": ["plugin:@nrwl/nx/typescript"],
+      "extends": ["plugin:@nx/typescript"],
       "rules": {
         "no-prototype-builtins": "off",
         "@typescript-eslint/no-explicit-any": "off",
@@ -41,7 +41,7 @@
     },
     {
       "files": ["*.js", "*.jsx"],
-      "extends": ["plugin:@nrwl/nx/javascript"],
+      "extends": ["plugin:@nx/javascript"],
       "rules": {}
     }
   ]