Rename CloudWatch o-tel commands to otel with hidden backward-compatibility

[gcacace]

Rename the 3 CloudWatch OTel enrichment CLI commands from o-tel to otel naming, consistent with the OpenTelemetry (https://opentelemetry.io/) community convention:

• get-o-tel-enrichment → get-otel-enrichment
• start-o-tel-enrichment → start-otel-enrichment
• stop-o-tel-enrichment → stop-otel-enrichment

The old o-tel names are kept as hidden aliases for backward compatibility using the existing rename_command / make_hidden_command_alias utilities.

Changes:

• Added awscli/customizations/cloudwatch.py with a building-command-table.cloudwatch event handler that renames the commands and registers hidden aliases.
• Registered the handler in awscli/handlers.py.
• Added functional tests verifying both old and new command names work.
• Added a changelog entry.