Update the ruleConfigs.json

I am working on adding code snippets of rule configuration to the Debugger dev guide.
I am referring to the following source codes in order to see what default collections are taken by each rule.

* https://github.com/awslabs/sagemaker-debugger-rulesconfig/blob/master/smdebug_rulesconfig/rule_config_jsons/ruleConfigs.json
* https://github.com/awslabs/sagemaker-debugger-rules/tree/master/smdebug_rules

In the [ruleConfigs.json](https://github.com/awslabs/sagemaker-debugger-rulesconfig/blob/master/smdebug_rulesconfig/rule_config_jsons/ruleConfigs.json), some rules have default collections, but some are missing them.
I suggest to add a default tensor collection to those rules that currently don't have it.

For example, in order for the XGBoost TreeDepth rule to work, we need to add the `tree` collection by default as following:

```
"TreeDepth": {
"DebugRuleConfiguration": {
"RuleConfigurationName": "TreeDepth",
"RuleParameters": {
"rule_to_invoke": "TreeDepth"
}
},
"CollectionConfigurations": [
{
"CollectionName": "tree",
"CollectionParameters": {
"save_interval": "500"
}
}
]
},
```

Start with ruleConfigs.json and compare its rule entries against the rule implementations in the smdebug_rules repository. Identify rules without required default tensor collections, using the XGBoost TreeDepth example as a reference, and update the configuration so each applicable rule has the needed defaults.

Written by the indexing model from the issue text.