Make database install/upgrade provider aware

Ground work for installing and upgrading database schema based upon DB provider (MySQL, PostgresSQL, SQL Server, etc.)

Cleaned up legacy cruft, refactored, commented and made simpler for to support additional database providers.

core/database/scripts/mysql/db_00017.sql

@@ -0,0 +1,32 @@
+/* enterprise edition */
+
+-- document needs proection and approval columns
+ALTER TABLE document ADD COLUMN `protection` INT NOT NULL DEFAULT 0 AFTER `template`;
+ALTER TABLE document ADD COLUMN `approval` INT NOT NULL DEFAULT 0 AFTER `protection`;
+
+-- page workflow status
+ALTER TABLE page ADD COLUMN `status` INT NOT NULL DEFAULT 0 AFTER `revisions`;
+
+-- links pending changes to another page
+ALTER TABLE page ADD COLUMN `relativeid` CHAR(16) DEFAULT '' NOT NULL COLLATE utf8_bin AFTER `status`;
+
+-- useraction captures what is being actioned 
+ALTER TABLE useraction ADD COLUMN `reftype` CHAR(1) DEFAULT 'D' NOT NULL COLLATE utf8_bin AFTER `iscomplete`;
+ALTER TABLE useraction ADD COLUMN `reftypeid` CHAR(16) NOT NULL COLLATE utf8_bin AFTER `reftype`;
+
+-- useractivity usage expansion
+ALTER TABLE useractivity ADD COLUMN `documentid` CHAR(16) DEFAULT '' NOT NULL COLLATE utf8_bin AFTER `sourceid`;
+ALTER TABLE useractivity ADD COLUMN `pageid` CHAR(16) DEFAULT '' NOT NULL COLLATE utf8_bin AFTER `documentid`;
+UPDATE useractivity SET documentid=sourceid WHERE sourcetype=2;
+ALTER TABLE useractivity DROP COLUMN `sourceid`;
+CREATE INDEX idx_useractivity_1 ON useractivity(orgid,documentid,sourcetype);
+CREATE INDEX idx_useractivity_2 ON useractivity(orgid,documentid,userid,sourcetype);
+
+-- clean-up
+DELETE FROM categorymember WHERE documentid NOT IN (SELECT refid FROM document);
+UPDATE page SET level=1 WHERE level=0;
+
+-- deprecations
+DROP TABLE IF EXISTS `audit`;
+DROP TABLE IF EXISTS `search_old`;
+ALTER TABLE document DROP COLUMN `layout`;