mariadb: improve packaging and configuration

At present there are some flaws related to configuration, also related
to the packaging of mariadb. For starters there are complaints that the
configuration is too static.

To address this a new configuration layout is introduced. The primary
configuration file (my.cnf) is changed so that it now only includes
further configuration files in the directory /etc/mysql/conf.d. More
default configuration files are added for the server and the client.
This is the new default configuration.

With these changes it's possible for the user to select if they want to
change the default configuration (in conf.d/*.cnf) or if they want to
drop their own files into conf.d instead. If the user .cnf files are
read after the default .cnf files (files are included in alphabetical
order), they will overwrite the settings from the default configuration.

The other flaw is that the my.cnf file is included in mariadb-server.
But that doesn't really fit the requirements, as the client also uses
the configuration file(s). To accomodate this a new package
mariadb-common is added. It installs the shared my.cnf file.

The remaining changes add base packages, both for the server and the
client. These are meant as foundation for the packages containing the
respective binaries. In summary they will install the configuration,
small miscellaneous files (SQL scripts etc.) and the user "mariadb".

That means that everything is ready for the binaries, like mysql and
mysqld. If there is not enough space left on flash memory, the user can
just drop the binaries on a pendrive, link them to /usr/bin and get
started.

The ideas and configuration files were copied from Debian. Some
amendments were made.

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>

utils/mariadb/conf/my.cnf

@@ -1,54 +1,22 @@
-[client]
-port		= 3306
-socket		= /var/run/mysqld/mysqld.sock
+# The MariaDB configuration file
+#
+# The MariaDB/MySQL tools read configuration files in the following order:
+# 1. "/etc/mysql/my.cnf" (this file) to set global defaults,
+# 2. "/etc/mysql/conf.d/*.cnf" to set global options.
+# 3. "~/.my.cnf" to set user-specific options.
+#
+# If the same option is defined multiple times, the last one will apply.
+#
+# One can use all long options that the program supports.
+# Run program with --help to get a list of available options and with
+# --print-defaults to see which it would actually understand and use.
 
-[mysqld]
-user		= mariadb
-socket		= /var/run/mysqld/mysqld.sock
-port		= 3306
-basedir		= /usr
-
-############ Don't put this on the NAND #############
-# Figure out where you are going to put the databases
-# And run mysql_install_db --force
-datadir		= /mnt/data/mysql/
-
-######### This should also not go on the NAND #######
-tmpdir		= /mnt/data/tmp/
-
-skip-external-locking
-
-bind-address		= 127.0.0.1
-
-# Fine Tuning
-key_buffer_size		= 16M
-max_allowed_packet	= 16M
-thread_stack		= 192K
-thread_cache_size	= 8
-
-# Here you can see queries with especially long duration
-#log_slow_queries	= /var/log/mysql/mysql-slow.log
-#long_query_time	= 2
-#log-queries-not-using-indexes
-
-# The following can be used as easy to replay backup logs or for replication.
-#server-id		= 1
-#log_bin		= /var/log/mysql/mysql-bin.log
-#expire_logs_days	= 10
-#max_binlog_size	= 100M
-#binlog_do_db		= include_database_name
-#binlog_ignore_db	= include_database_name
-
-
-[mysqldump]
-quick
-quote-names
-max_allowed_packet	= 16M
-
-[mysql]
-#no-auto-rehash	# faster start of mysql but no tab completition
-
-[isamchk]
-key_buffer		= 16M
+#
+# This group is read both both by the client and the server
+# use it for options that affect everything
+#
+[client-server]
 
+# Import all .cnf files from configuration directory
+!includedir /etc/mysql/conf.d/