CI: Deprecate init-meta job, improve Meta Bump Bot and set INITENV_INTERACTIVE

This MR contains:

• Deprecation of init-meta job (see commit message for more information)
• Some fixes/improvements for the meta bump bot template
• Setting of env variable INITENV_INTERACTIVE which enables non-interactive mode in scripts (see pending MR: !37 (merged))

Tests were done in build-ktn-imx using this branch: https://git.kontron-electronics.de/sw/yocto/build-ktn-imx/-/commits/feature/ci-remove-init-meta.

FYI: @jbauknecht