Allow having tenants with different domains

Some institutions using CONSUL have expressed interest in this feature
since some of their tenants might already have their own domains.

We've considered many options for the user interface to select whether
we're using a subdomain or a domain, like having two separate fields,
using a check box, ... In the end we've chosen radio buttons because
they make it easier to follow a logical sequence: first you decide
whether you're introducing a domain or subdomain, and then you enter it.

We've also considered hiding this option and assuming "if it's got a
dot, it's a domain". However, this wouldn't work with nested subdomains
and it wouldn't work with domains which are simply machine names.

Note that a group of radio buttons (or check boxes) is difficult to
style when the text of the label might expand over more than one line
(as is the case here on small screens); in this case, most solutions
result in the second line of the label appearing immediately under the
radio button, instead of being aligned with the first line of the label.
That's why I've added a container for the input+label combination.

db/migrate/20221120123254_add_schema_type_to_tenants.rb

@@ -0,0 +1,5 @@
+class AddSchemaTypeToTenants < ActiveRecord::Migration[6.0]
+  def change
+    add_column :tenants, :schema_type, :integer, null: false, default: 0
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2022_09_15_154808) do
+ActiveRecord::Schema.define(version: 2022_11_20_123254) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -1561,6 +1561,7 @@ ActiveRecord::Schema.define(version: 2022_09_15_154808) do
     t.string "schema"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.integer "schema_type", default: 0, null: false
     t.index ["name"], name: "index_tenants_on_name", unique: true
     t.index ["schema"], name: "index_tenants_on_schema", unique: true
   end