add mastodon logo

public/svg/mastodon.svg

+<svg xmlns="http://www.w3.org/2000/svg" width="61.076954mm" height="65.47831mm" viewBox="0 0 216.4144 232.00976">
+  <path fill="#2b90d9" d="M211.80734 139.0875c-3.18125 16.36625-28.4925 34.2775-57.5625 37.74875-15.15875 1.80875-30.08375 3.47125-45.99875 2.74125-26.0275-1.1925-46.565-6.2125-46.565-6.2125 0 2.53375.15625 4.94625.46875 7.2025 3.38375 25.68625 25.47 27.225 46.39125 27.9425 21.11625.7225 39.91875-5.20625 39.91875-5.20625l.8675 19.09s-14.77 7.93125-41.08125 9.39c-14.50875.7975-32.52375-.365-53.50625-5.91875C9.23234 213.82 1.40609 165.31125.20859 116.09125c-.365-14.61375-.14-28.39375-.14-39.91875 0-50.33 32.97625-65.0825 32.97625-65.0825C49.67234 3.45375 78.20359.2425 107.86484 0h.72875c29.66125.2425 58.21125 3.45375 74.8375 11.09 0 0 32.975 14.7525 32.975 65.0825 0 0 .41375 37.13375-4.59875 62.915"/>
+  <path fill="#fff" d="M177.50984 80.077v60.94125h-24.14375v-59.15c0-12.46875-5.24625-18.7975-15.74-18.7975-11.6025 0-17.4175 7.5075-17.4175 22.3525v32.37625H96.20734V85.42325c0-14.845-5.81625-22.3525-17.41875-22.3525-10.49375 0-15.74 6.32875-15.74 18.7975v59.15H38.90484V80.077c0-12.455 3.17125-22.3525 9.54125-29.675 6.56875-7.3225 15.17125-11.07625 25.85-11.07625 12.355 0 21.71125 4.74875 27.8975 14.2475l6.01375 10.08125 6.015-10.08125c6.185-9.49875 15.54125-14.2475 27.8975-14.2475 10.6775 0 19.28 3.75375 25.85 11.07625 6.36875 7.3225 9.54 17.22 9.54 29.675"/>
+</svg>
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