feat: added `electrum` and `esplora` support to `TestEnv` #27

Job	Run time
Check no_std	35s
clippy_check	5m 1s
Check WASM	56s
Rust fmt	6s
Build and test (stable, true, --no-default-features)	4m 16s
Build and test (stable, true, --all-features)	2m 2s
Build and test (1.57.0, --no-default-features)	3m 1s
Build and test (1.57.0, --all-features)	7m 51s
	23m 48s

Provide feedback