MCOL-3551 Use generic MariaDB Server paths

This branch enforces the use of generic MariaDB server paths for their
binaries and data rather than custom paths.

/usr/local/mariadb/columnstore is now only for columnstore with this
patch.

It should be noted that this removes the auto-mounting of external
MariaDB UM data storage for AWS.

This is also a fix for MCOL-3510 after buildbot changes are made.

Also... MCOL-3552 Use columnstore.cnf to load plugins

The ColumnStore plugins now load using a columnstore.cnf instead of a
SQL sequence to be more in-line with MariaDB's methods.

oam/install_scripts/columnstoreLogRotate.in

@@ -18,12 +18,3 @@
 	copy
     olddir @ENGINE_SYSCONFDIR@/columnstore
 }
-/usr/local/mariadb/columnstore/mysql/db/*.err {
-    missingok
-    rotate 7
-    daily
-    dateext
-	copytruncate
-    olddir /usr/local/mariadb/columnstore/mysql/db
-    su root root
-}