ObservableProperty Attribute for Class

### Overview

To simplify the Observable Property attribute required for all properties inside the class.

Current Usage:
```
public partial class AddContact : ObservableObject
{
[ObservableProperty] private Guid id;
[ObservableProperty] private string firstName;
[ObservableProperty] private string lastName;
[ObservableProperty] private Phone phone;
[ObservableProperty] private DateTime? expiry;
[ObservableProperty] private ObservableCollection extraPhones = new();
[ObservableProperty] private string image;
[ObservableProperty] private Group group;
[ObservableProperty] private string email;
[ObservableProperty]
[NotifyPropertyChangedFor(nameof(ShowRingtonePlay))]
[NotifyPropertyChangedFor(nameof(RingtoneFile))]
private string ringtone;
public bool ShowRingtonePlay => !Ringtone.IsNullOrEmpty();
public string RingtoneFile => Path.GetFileName(Ringtone);
[ObservableProperty] private ObservableCollection emails = new();
[ObservableProperty] private Company company;
[ObservableProperty] private Country country;
[ObservableProperty] private Relationship relationship;
[ObservableProperty] private Address address;
[ObservableProperty] private ObservableCollection events = new();
[ObservableProperty] private ObservableCollection socials = new();
[ObservableProperty] private ObservableCollection notes = new();

private readonly CountryService countryService;
}
```
### API breakdown

No Api breakdown

### Usage example

```
[ObservableProperty] or [AllObservableProperty]
public partial class AddContact : ObservableObject
{
private Guid id;
private string firstName;
private string lastName;
private Phone phone;
private DateTime? expiry;
private ObservableCollection extraPhones = new();
private string image;
private Group group;
private string email;
private ObservableCollection emails = new();
private Company company;
private Country country;
private Relationship relationship;
private Address address;
private ObservableCollection events = new();
private ObservableCollection socials = new();
private ObservableCollection notes = new();

[NotifyPropertyChangedFor(nameof(ShowRingtonePlay))]
[NotifyPropertyChangedFor(nameof(RingtoneFile))]
private string ringtone;

public bool ShowRingtonePlay => !Ringtone.IsNullOrEmpty();
public string RingtoneFile => Path.GetFileName(Ringtone);

private readonly CountryService countryService;
}
```

### Breaking change?

No

### Alternatives

No

### Additional context

For much better code.

For automatic code generation, avoid public property and private readonly property.

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