test: Maybe add bitcoind binary in .github?

[rajarshimaitra]

We require the bitcoind binary for every build. This is due to the usage to bitcoind crate for our integration tests.

Currently for every github action build run, bitcoind is downloaded. As defined here https://github.com/utxo-teleport/teleport-transactions/blob/dda5c2d9c80cec6ccaec13b5d5038fc10c3a6d53/src/test_framework.rs#L89

This often causes unmitigable test failure in our CI when the set URL to download bitcoind is unresponsive for any reason. This also increases our CI build time, as downloading the binary takes some time.

It is possible to provide a path to bitcoind in the above command instead of from_downloaded. We can keep the bitcoind in our .github folder as pass that path in the BitcoinD build call.

ps: This will increase our repo sizew. We will be literally shipping bitcoind with our repo. This won't increase the final binary size of our code though.