Improve Gradle command error messages

[godrei]

Checklist

• I've read and followed the Contribution Guidelines
• step.yml and README.md is updated with the changes (if needed)

Version

Requires a MINOR version update

Context

This PR improves the error messages logged by the Step. Currently, the step prints the whole output of the gradle dependencies command into the error message, which makes it noisy.
The primary goal was logging relevant messages when gradle dependencies fails.

Resolves: https://bitrise.atlassian.net/browse/BIVS-1951

Changes

• Create dedicated error structs for gradle dependencies command-related errors, to standardize command failure errors
• gradle dependencies command's stderr is used as a failure reason
• Split the main func into AndroidToolsInstaller.ProcessInputs and AndroidToolsInstaller.Run and wire in formatted error messages

Investigation details

Initially, I started by writing a custom parser to gather relevant details from the Gradle command execution output, but it turned out Gradle prints the failure reason to the stderr.

Decisions

gradle dependencies command's stderr might contain a stacktrace, which can be a long message. We might consider truncating it, in the future if it causes too much noise in the error messages.