* Replace Zcash parameters crates with pre-downloaded local parameter files
* Download Zcash parameters using the `zcashd` script in CI and Docker
* Add a zcash_proofs dependency to zebra-consensus
* Download Sapling parameters using zcash_proofs, rather than fetch-params.sh
* Add a new `zebrad download` subcommand
This command isn't required for nomrmal usage.
But it's useful when testing, or launching multiple Zebra instances.
* Use `zebrad download` in CI to pre-download parameters
* Log a helpful hint if downloading fails
* Allow some duplicate dependencies currently hidden by orchard
* Spawn a separate task to download Groth16 parameters
* Run the parameter download with code coverage
This avoids re-compining Zebra with and without coverage.
* Update Cargo.lock after rebase
* Try to pass `download` as an argument to `zebrad` in coverage CI
* Fix copy and paste comment typos
* Add path and download examples, like zcash_proofs
* Download params in CI just like zcash_proofs does
* Delete a redundant build step
* Implement graceful shutdown for zebrad start
* Send coverage summary to /dev/null when getting the params path
* Use the correct parameters path and download commands in CI
* Explain pre-downloads
* Avoid calling params_folder twice
* Rename parameter types and methods for consistency
```sh
fastmod SaplingParams SaplingParameters zebra*
fastmod Groth16Params Groth16Parameters zebra*
fastmod PARAMS GROTH16_PARAMETERS zebra*
fastmod params_folder directory zebra*
```
And a manual variable name tweak.
* rustfmt
* Remove a redundant coverage step
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>