Add `ElectrumClient::server_features` method #1188

Job	Run time
Build and test macOS x86_64 wheels (3.8)	5m 54s
Build and test macOS arm64 wheels (3.8)	6m 40s
Build and test macOS x86_64 wheels (3.9)	5m 53s
Build and test macOS arm64 wheels (3.9)	8m 35s
Build and test macOS x86_64 wheels (3.10)	6m 9s
Build and test Windows wheels (3.8)	5m 27s
Build and test macOS arm64 wheels (3.10)	5m 51s
Build and test Manylinux 2.28 x86_64 wheels (cp38-cp38)	3m 45s
Build and test macOS x86_64 wheels (3.11)	6m 54s
Build and test macOS arm64 wheels (3.11)	6m 35s
Build and test macOS x86_64 wheels (3.12)	6m 29s
Build and test Manylinux 2.28 x86_64 wheels (cp39-cp39)	3m 38s
Build and test Windows wheels (3.9)	5m 57s
Build and test macOS arm64 wheels (3.12)	8m 14s
Build and test Manylinux 2.28 x86_64 wheels (cp310-cp310)	3m 46s
Build and test Windows wheels (3.10)	5m 57s
Build and test Manylinux 2.28 x86_64 wheels (cp311-cp311)	3m 43s
Build and test Windows wheels (3.11)	5m 26s
Build and test Manylinux 2.28 x86_64 wheels (cp312-cp312)	3m 53s
Build and test Windows wheels (3.12)	6m 21s
	1h 55m 7s

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