r/vstp*: use new provider via framework

[jeremmfr]

ENHANCEMENTS:

• resource/junos_vstp: resource now use new terraform-plugin-framework
  some of config errors are now sent during Plan instead of during Apply
  optional boolean attributes doesn't accept value false
• resource/junos_vstp_interface: resource now use new terraform-plugin-framework
  some of config errors are now sent during Plan instead of during Apply
  optional boolean attributes doesn't accept value false
• resource/junos_vstp_vlan: resource now use new terraform-plugin-framework
  some of config errors are now sent during Plan instead of during Apply
  optional boolean attributes doesn't accept value false
• resource/junos_vstp_vlan_group: resource now use new terraform-plugin-framework
  some of config errors are now sent during Plan instead of during Apply
  optional boolean attributes doesn't accept value false