…T Methods are configured for tables/views (#1607)

- Closes #1571 #1570
- At the moment, CLI writes out all the 5 HTTP methods to the config
file when adding an entity backed by table/view.

![image](https://github.com/Azure/data-api-builder/assets/11196553/206ddffb-a2d5-42c5-94dd-50165ef96f24)

- However, for tables/views, the `Methods` property does not play any
role and can be skipped writing to the config file.

- `EntityRestOptions`: `Methods` property is made nullable. References
where it was initialized with an empty array is updated to `null`.
Appropriate `null` checks are added.
- `EntityRestOptionsConverter`: Serialization logic is updated to write
to the config file only when the `Methods` within REST element is not
empty
- `RuntimeConfigValidator.ValidatePresenceOfExtraRestProperties()`:
Helper method to log a warning message when `Methods` property is added
manually to an entity backed by table/view.
- HTTP Actions are removed from the snapshot files.
- `dab-config.*` files - `Methods` property is removed from the
reference config files

- [x] Integration Tests
- [x] Unit Tests
- [x] Manual Tests

- CLI: REST actions are not written to the config file
`dab add books --source books --permissions "anonymous:*"`

Config Json created:
```json
"entities": {
    "books": {
  "source": {
    "object": "books",
    "type": "table"
  },
  "graphql": {
    "enabled": true,
    "type": {
      "singular": "books",
      "plural": "books"
    }
  },
  "rest": {
    "enabled": true
  },
  "permissions": [
    {
      "role": "anonymous",
      "actions": [
        {
          "action": "*"
        }
      ]
    }
  ]
}
  }
```
- When the config file is hand-edited to add `methods` property to a
table/view, engine logs a warning message during start-up

Config:
```json
"Book": {
      "source": {
        "object": "books",
        "type": "table"
      },
      "rest": {
        "enabled": true,
        "methods": [
          "get",
          "post"
        ]
      },
      "graphql": {
        "enabled": true,
        "type": {
          "singular": "book",
          "plural": "books"
        }
      },
```
Warning Logged:

![image](https://github.com/Azure/data-api-builder/assets/11196553/287efcc2-e088-48b1-81f1-f762e18c2b51)

#1646)

- Cherry Picks [PR
1607](#1607) to
`release/0.8`