feat: import/export current fit as EFT string (#51)

Sadly, due to browser protection, we cannot just read the clipboard at
will. So instead, you get a textarea where you have to paste your fit
in.

src/FitButtonBar/FitButtonBar.module.css

@@ -25,6 +25,10 @@
     height: 20px;
     line-height: 20px;
 }
+.buttonMax {
+    text-align: center;
+    width: calc(100% - 40px - 2px);
+}
 
 .button:hover {
     background-color: #864735;
@@ -67,21 +71,41 @@
     padding: 10px;
 }
 
+.popup > div > .button {
+    margin-top: 10px;
+}
+.popup > div > .button:first-child {
+    margin-top: 0;
+}
+
 .renameEdit {
     margin-right: 10px;
 }
 
 .alreadyExists {
-    text-align: center;
     max-width: 50%;
 }
 
 .alreadyExistsButtons {
     margin-top: 10px;
-    text-align: center;
 }
 .alreadyExistsButtons .button {
     margin-right: 10px;
-    width: 35%;
+    text-align: center;
+    width: calc(50% - 48px);
+}
+.alreadyExistsButtons .button:last-child {
+    margin-right: 0;
+}
+
+.paste .button {
+    text-align: center;
+    width: calc(100% - 42px);
+}
+.pasteTextarea {
+    height: 60px;
+    margin-bottom: 10px;
+    margin-top: 4px;
+    width: 300px;
 }