[REQ] [typescript-angular] support for object query parameters as nested key/json string

Created by: dougal83

Is your feature request related to a problem? Please describe.

Cannot consume . notation query parameters objects in a current project.

Describe the solution you'd like

Extend support to include option to configure how objects are encoded in query parameters. To include options for nested keys and JSON string.

Describe alternatives you've considered

Support . notation in current project but that would not solve the issue for others.

Additional context

Suggest change (as an option):

https://github.com/OpenAPITools/openapi-generator/blob/603709e17e318b22177f7dff193f65cf8527dbcf/modules/openapi-generator/src/main/resources/typescript-angular/api.service.mustache#L181

key != null ? `${key}[${k}]` : k,

Also, add option to JSON stringify the object.

See: #4407