workflows: add debug input for sync templates act (#7057)

# Description

Introduce a workflow `debug` input for `misc-sync-templates.yml` and use
it instead of the `runner.debug` context variable, which is set to '1'
when `ACTIONS_RUNNER_DEBUG` env/secret is set
(https://docs.github.com/en/actions/monitoring-and-troubleshooting-workflows/troubleshooting-workflows/enabling-debug-logging#enabling-runner-diagnostic-logging).
This is useful for controlling when to show debug prints.

## Integration

N/A

## Review Notes

Using `runner.debug` requires setting the `ACTIONS_RUNNER_DEBUG` env
variable, but setting it to false/true is doable through an input, or by
importing a variable from the github env file (which requires a code
change). This input alone can replace the entire `runner.debug` +
`ACTIONS_RUNNER_DEBUG` setup, which simplifies debug printing, but it
doesn't look as standard as `runner.debug`. I don't think it is a big
deal overall, for this action alone, but happy to account for other
opinions.

Note: setting the `ACTIONS_RUNNER_DEBUG` whenever we want in a separate
branch wouldn't be useful because we can not run the
`misc-sync-templates.yml` action from other branch than `master` (due to
branch protection rules), so we need to expose this input to be
controllable from `master`.

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Signed-off-by: Iulian Barbu <[email protected]>