Replace diacriticless-Module with optimized internal alternative (#842)

As the npm-Module "diacriticless" is highly inefficient when replacing
dicritics (it iterates thousands of times multiple arrays) and the
author does not merge the proposed pull-request with a very optimized
routine of this, this optimization is now implemented locally in
vue-good-table. As #545
states, there is a performanceproblem because of the
diacriticless-implementation. So this could help fixing this issue as
well.

package.json

@@ -43,7 +43,6 @@
   },
   "dependencies": {
     "date-fns": "^2.17.0",
-    "diacriticless": "1.0.1",
     "lodash.isequal": "^4.5.0"
   },
   "devDependencies": {

src/components/types/default.js

@@ -1,4 +1,4 @@
-import diacriticless from 'diacriticless';
+import { diacriticless } from '../utils/diacritics';
 
 const escapeRegExp = str => str.replace(/[\\^$*+?.()|[\]{}]/g, '\\$&');