Route for adding new application member

- domain method for creating a new application member
- ApplicationInvitations domain class
- nested form for adding a new user that holds user data, application
  permission sets, and environment roles
- Invitation service can infer invitation type based on role it's given
- new invitation email templates

atst/forms/application_member.py

@@ -0,0 +1,41 @@
+from wtforms.fields import FormField, FieldList, HiddenField, BooleanField
+
+from .forms import BaseForm
+from .member import NewForm as BaseNewMemberForm
+from .data import ENV_ROLES
+from atst.forms.fields import SelectField
+from atst.domain.permission_sets import PermissionSets
+
+
+class EnvironmentForm(BaseForm):
+    environment_id = HiddenField()
+    environment_name = HiddenField()
+    role = SelectField(environment_name, choices=ENV_ROLES, default=None)
+
+
+class PermissionsForm(BaseForm):
+    perms_env_mgmt = BooleanField(None, default=False)
+    perms_team_mgmt = BooleanField(None, default=False)
+    perms_del_env = BooleanField(None, default=False)
+
+    @property
+    def data(self):
+        _data = super().data
+        perm_sets = []
+
+        if _data["perms_env_mgmt"]:
+            perm_sets.append(PermissionSets.EDIT_APPLICATION_ENVIRONMENTS)
+
+        if _data["perms_team_mgmt"]:
+            perm_sets.append(PermissionSets.EDIT_APPLICATION_TEAM)
+
+        if _data["perms_del_env"]:
+            perm_sets.append(PermissionSets.DELETE_APPLICATION_ENVIRONMENTS)
+
+        return perm_sets
+
+
+class NewForm(BaseForm):
+    user_data = FormField(BaseNewMemberForm)
+    permission_sets = FormField(PermissionsForm)
+    environment_roles = FieldList(FormField(EnvironmentForm))

atst/forms/data.py

@@ -1,3 +1,4 @@
+from atst.models import CSPRole
 from atst.utils.localization import translate, translate_duration
 from atst.models.environment_role import CSPRole