Cleanup docker images after build

[Lohann]

Description

When running ./build_connectors.sh many times, dangling images get accumulated locally, also because of the multi-stage build it now builds two images per connector. This PR fixes the script for properly cleanup the images after build.

References:

• Docker doesn't override images after each build: https://stackoverflow.com/a/52477584
• Docker store all intermediary multi-stage images: https://stackoverflow.com/a/55082473

Changes

• Automatically remove dangling images after each build
• Properly set docker image labels, which wasn't working
• Check docker image labels after each build
• Display more useful information in the ./build_connectors.sh output
• Fix ./reset_docker.sh script for skip docker builtin networks
• Add Shellcheck on CI
• Move all scripts to ./scripts folder

Type of change

• New feature (non-breaking change which adds functionality)

Code review prechecks:

• Code follows the style guidelines of this project
• Code has been self-reviewed
• Inline comments have been added for each method
• I have made corresponding changes to the documentation
• Code changes introduces no new problems or warnings
• Test cases have been added
• Dependent changes have been merged and published in downstream modules

[penumbra23]

Legit!