feat: add ability to run a script once network is initialized

[brunopgalvao]

Simple test:

cargo run up parachain -f ./tests/zombienet.toml -p https://github.com/r0gue-io/pop-node --cmd "echo Hello from Pop CLI"

[codecov]

Codecov Report

Attention: Patch coverage is 82.75862% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 50.61%. Comparing base (48eec26) to head (c9f9345).
Report is 6 commits behind head on main.

@@            Coverage Diff             @@
##             main     #180      +/-   ##
==========================================
+ Coverage   49.69%   50.61%   +0.91%     
==========================================
  Files          32       32              
  Lines        2785     2857      +72     
  Branches     2785     2857      +72     
==========================================
+ Hits         1384     1446      +62     
- Misses       1182     1186       +4     
- Partials      219      225       +6     

Files	Coverage Δ
crates/pop-cli/src/commands/up/parachain.rs	18.18% <82.75%> (+18.18%)	⬆️

... and 4 files with indirect coverage changes

[AlexD10S]

Some comments:

• We need to explain this option in the README and if is with an useful example on how can be useful for devs much better.
• If I run the example --cmd "echo Hello from Pop CLI" as you suggest for a quick test it looks a bit weird, it gets stuck for a few seconds in Running command: echo Hello from Pop CLI... without really executing it and after it clear the screen to display the information of the pop up. UX has to be improved, maybe showing the message that is running the command after spawn the networks?
• I left a comment about parsing the arguments of the script: pop up -cmd "echo" --args ...

[peterwht]

This would be good to test with a simple Subxt script that connects to the launched network.

[brunopgalvao]

This would be good to test with a simple Subxt script that connects to the launched network.

Created a simple script.

git clone https://github.com/brunopgalvao/set-balance
cd set-balance
cargo build

./tests/zombienet.toml

[relaychain]
chain = "rococo-local"

[[relaychain.nodes]]
name = "alice"
rpc_port = 8833
validator = true

[[relaychain.nodes]]
name = "bob"
validator = true

pop up parachain -f ./tests/zombienet.toml -r v1.8.0 -p --cmd /Users/bruno/src/set-balance/target/debug/set-balance

Output

[AlexD10S]

This would be good to test with a simple Subxt script that connects to the launched network.

Thanks, LGTM now!
This example makes it easier to test the function. I have added an issue in the documentation to convert this example into a tutorial: r0gue-io/pop-docs#2