Sending sigterm to terminate `cloud-sql-proxy`

[jaroslaw-pieszka]

Description

Sending sigterm allows to exit proxy with 0 code (if properly configured).

Changes proposed in this pull request:

• sending signal
• logging if process was found and signal sent

Related issue(s)

[vvxxvvxx]

Hi @jaroslaw-pieszka , --exit-zero-on-sigterm also needs to be added for provisioner as it also uses migrator, right? as the places changed in https://github.com/kyma-project/control-plane/pull/3444/files