[BUGFIX] Remove "NOT NULL" annotation from text fields

Seems that TYPO3 also does not use it for "text"
fields

Related: #1342

Author: mschwemer

ext_tables.sql

@@ -32,14 +32,14 @@ CREATE TABLE tx_powermail_domain_model_field (
 	page int(11) unsigned DEFAULT '0' NOT NULL,
 	title varchar(255) DEFAULT '' NOT NULL,
 	type varchar(255) DEFAULT '' NOT NULL,
-	settings text NOT NULL,
+	settings text,
 	path varchar(255) DEFAULT '' NOT NULL,
 	content_element int(11) DEFAULT '0' NOT NULL,
-	text text NOT NULL,
-	prefill_value text NOT NULL,
-	placeholder text NOT NULL,
-	placeholder_repeat text NOT NULL,
-	create_from_typoscript text NOT NULL,
+	text text,
+	prefill_value text,
+	placeholder text,
+	placeholder_repeat text,
+	create_from_typoscript text,
 	validation int(11) DEFAULT '0' NOT NULL,
 	validation_configuration varchar(255) DEFAULT '' NOT NULL,
 	css varchar(255) DEFAULT '' NOT NULL,
@@ -73,10 +73,10 @@ CREATE TABLE tx_powermail_domain_model_mail (
 	sender_mail varchar(255) DEFAULT '' NOT NULL,
 	subject varchar(255) DEFAULT '' NOT NULL,
 	receiver_mail varchar(1024) DEFAULT '' NOT NULL,
-	body text NOT NULL,
+	body text,
 	feuser int(11) DEFAULT '0' NOT NULL,
 	sender_ip tinytext NOT NULL,
-	user_agent text NOT NULL,
+	user_agent text,
 	time int(11) DEFAULT '0' NOT NULL,
 	form int(11) DEFAULT '0' NOT NULL,
 	answers int(11) unsigned DEFAULT '0' NOT NULL,
@@ -99,7 +99,7 @@ CREATE TABLE tx_powermail_domain_model_mail (
 CREATE TABLE tx_powermail_domain_model_answer (
 	mail int(11) unsigned DEFAULT '0' NOT NULL,
 
-	value text NOT NULL,
+	value text,
 	value_type int(11) unsigned DEFAULT '0' NOT NULL,
 	field int(11) unsigned DEFAULT '0' NOT NULL,