Allow starting the CLI with an initial pwd set

[piotrMocz]

This was mentioned as a half-measure for #8 and it seems to cover a lot of the use cases (assuming users start drink-cli to mostly work on one contract.

Usage:

$ drink-cli --help
Usage: drink-cli [OPTIONS]

Options:
  -p, --path <DIRECTORY>  Starts the CLI in the provided directory
  -h, --help              Print help
  -V, --version           Print version

So you're able to start it like:

$ drink-cli examples/flipper

And immediately call build.

[pmikolajczyk41]

when I run: cargo run --release -- -p /home/<my local path>/drink/examples/flipper, optionally build the contract and try to deploy it, I get error about finding contract file

this helps:

fn find_wasm_blob(pwd: &PathBuf) -> Option<(String, PathBuf)> {
    let Ok(entries) = fs::read_dir(pwd.join("target/ink")) else {