- in `keyvalue.rs`, `memory.rs`, `sqlite.rs` use the `run_tests_with_init`
 macro to run database tests.

 - in `wallet/mod.rs` update all the test calls from macro to function for
 `populate_test_db`.

 - some import fixes in `address_validator.rs` and `psbt/mod.rs`.

Co-authored-by: SanthoshAnguluri <santhoshanguluri15@gmail.com>
Co-authored-by: saikishore222 <saikishore.chsk@gmail.com>

Similar to the database `run_test_with_init` another `make_blockchain_test`
macro is added, which will run the blockchain tests given a initilizer
function.

These test functions are taken out of the macro and are placed as their own
public functions.

A doc comment explaining how to use the tests externally from bdk is
added before the `blockchain_tests::test` module.

Co-authored-by: SanthoshAnguluri <santhoshanguluri15@gmail.com>
Co-authored-by: saikishore222 <saikishore.chsk@gmail.com>

Apply the new `make_blockchain_test` macro to run the blockchain tests
for rpc, electrum and esplora blockchain.

Co-authored-by: SanthoshAnguluri <santhoshanguluri15@gmail.com>
Co-authored-by: saikishore222 <saikishore.chsk@gmail.com>

Co-authored-by: SanthoshAnguluri <santhoshanguluri15@gmail.com>
Co-authored-by: saikishore222 <saikishore.chsk@gmail.com>

This method is only relevant for testing, so we make the
`Wallet::database` field `pub(crate)`.