Change from single user (config) to database based multi user system.

[fnkbsi]

Implements multi user access. Uses the steve database to store the "webusers" and their roles. Privileges on websites are set in the source code in SecurityConfiguration.java. Sites for administration of the "webuser" included. May fixes #991

[juherr]

@goekay Please, review. The change will improve the product a lot.

[fluppie]

nice, hope this will be merged soon :-)!

[goekay]

this PR is next on my TODO list. starting to review it.

[goekay]

@fnkbsi could you pls undo useless/whitespace/stylistic changes which would make it easier for me to see the real changes?