Proposed changes

Add a new systemd service template to handle the certificate renewal when using a Cumulocity mapper with cloud profiles. The previous service tedge-cert-renewer@.service isn't able to support cloud profiles as the template variable (the part after the @ sign) is used for the mapper type, and not the cloud profile name.

The new tedge-cert-renewer-c8y@.timer unit (not the -c8y before the @ sign!) will be automatically activated when the tedge-mapper-c8y@.service is enabled/created. The timer then will trigger the corresponding tedge-cert-renewer-c8y@.service which then does the actual certificate renewal commands for the given cloud profile.

Note: You can manually enable and start the renewal process for a given Cumulocity cloud profile using the following commands:

systemctl enable tedge-cert-renewer-c8y@second.timer
systemctl start tedge-cert-renewer-c8y@second.timer

The PR also included an extension to the existing cloud profiles documentation to provide an end-to-end example of how to setup a second connection and going into some details about why (to reflect a customer scenario).

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

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Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s. You can activate automatic signing by running just prepare-dev once)
• I ran just format as mentioned in CODING_GUIDELINES
• I used just check as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments