feat: add GitHub Sponsors support

- Add FUNDING.yml to enable sponsor button
- Add SPONSORS.md with tier information

.github/FUNDING.yml

@@ -0,0 +1,15 @@
+# These are supported funding model platforms
+
+github: [affaan-m]
+# patreon: # Replace with a single Patreon username
+# open_collective: # Replace with a single Open Collective username
+# ko_fi: # Replace with a single Ko-fi username
+# tidelift: # Replace with a single Tidelift platform-name/package-name e.g., npm/babel
+# community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-hierarchical-namespace-controller
+# liberapay: # Replace with a single Liberapay username
+# issuehunt: # Replace with a single IssueHunt username
+# lfx_crowdfunding: # Replace with a single LFX Crowdfunding project-name e.g., cloud-hierarchical-namespace-controller
+# polar: # Replace with a single Polar username
+# buy_me_a_coffee: # Replace with a single Buy Me a Coffee username
+# thanks_dev: # Replace with a single thanks.dev username
+custom: ['https://ecc.tools']