autoscaler: Allow customization of taskscaler and fleeting parameters in config.toml
## Description
Both `taskscaler` and `fleeting` have internal configuration options that are not currently exposed to users for customization.
## Proposal
Expose internal configuration parameters such as `DeletionRetryInterval`, `FailureThreshold`, `ShutdownDeletionInterval`, and `ShutdownDeletionRetries` as configurable options in config.toml.
This would allow administrators to fine-tune these values based on their specific needs or infrastructure requirements.
## Links to related issues and merge requests / references
[fleeting: options.go](https://gitlab.com/gitlab-org/fleeting/fleeting/-/blob/main/options.go)
issue