RFC: Add support for lambda resource policies and attributes for custom category

### Is this feature request related to a new or existing Amplify category?

custom

## Add support for lambda resource policies and attributes for custom category

Hi, would like to seek community's feedback on below proposal for Custom Category enhancement.

### Summary

Amplify Custom Category does not support lambda resources. Below proposes a new file that developers can define CRUD policy actions and attributes that can be used in functions when added as a dependency resource.

### Current



### Describe the solution you'd like
---
EDIT:
- 16 Mar - Updated resources.json to support multiple policies in create, update, read, delete.
---

1) Introduce a new file 'resources.json' in the category folder

e.g. AWS::SecretsManager::Secret
amplify -> backend -> custom -> Secrets -> resources.json

2) Resources will be loaded by Functions when trying to set custom resources

Example resources.json:
```json
{
"policies": {
"create": [],
"update": [],
"read": [
{
"Action": [
"secretsmanager:GetSecretValue"
],
"Resource": [
{
"Ref": "${categoryName}${resourceName}Arn"
}
]
}
],
"delete": []
},
"attributes": [
"Arn",
"Name"
]
}
```

Example Secrets Manager CF Template:
```yaml
AWSTemplateFormatVersion: "2010-09-09"

Parameters:
env:
Type: String
Conditions:
ShouldNotCreateEnvResources: !Equals [!Ref env, NONE]
Resources:
Secrets:
Type: AWS::SecretsManager::Secret
Properties:
Name: !Join ["", [!Ref "AWS::StackName", "-secrets-", !Ref env]]
Outputs:
Arn:
Description: Secrets ARN
Value: !Ref Secrets
Name:
Description: Secrets Name
Value: !Join ["", [!Ref "AWS::StackName", "-secrets-", !Ref env]]

```

Example Output CLI:

Example Output function-parameters.json:

Example Output Function CF Template:



### Describe alternatives you've considered

To be discussed.

### Additional context

Please refer to Pull Request #9090

### Is this something that you'd be interested in working on?

- [X] 👋 I may be able to implement this feature request
- [ ] ⚠️ This feature might incur a breaking change

Start by reviewing the custom category handling and the proposed resources.json, then compare the referenced PR #9090 with the function-parameters.json and CloudFormation examples in this issue. Done means the agreed design supports custom-category Lambda resource policies and attributes when functions use the resource as a dependency.

Written by the indexing model from the issue text.