Updated Issue template

Author: PalmaAnd

.github/ISSUE_TEMPLATE/leetcode_problem.md renamed to .github/ISSUE_TEMPLATE/lc_easy_problem.md

@@ -1,6 +1,6 @@
 ---
 name: "LeetCode Easy Problem"
-about: "New LeetCode problem that will be worked on"
+about: "Easy LeetCode problem"
 assignees: "PalmaAnd"
 labels: "Leetcode,easy"
 ---

.github/ISSUE_TEMPLATE/lc_hard_problem.md

@@ -0,0 +1,14 @@
+---
+name: "LeetCode Hard Problem"
+about: "Hard LeetCode problem"
+assignees: "PalmaAnd"
+labels: "Leetcode,hard"
+---
+
+## Problem name
+
+**Link to the problem:** 
+
+**Description:**
+
+---

.github/ISSUE_TEMPLATE/lc_medium_problem.md

@@ -0,0 +1,14 @@
+---
+name: "LeetCode Medium Problem"
+about: "Medium LeetCode problem"
+assignees: "PalmaAnd"
+labels: "Leetcode,medium"
+---
+
+## Problem name
+
+**Link to the problem:** 
+
+**Description:**
+
+---