Added support for subdirectories. Made path usage safer by only allowing alphanumeric chars, dashes, underscores and dots. Directories are seperated by dots to mimic current config-group syntax. And to underline that directories are only the way of grouping within the file storage engine and thus not necessarily dirs.
Added support for subdirectories.
Made path usage safer by only allowing alphanumeric chars, dashes, underscores and dots. Directories are seperated by dots to mimic current config-group syntax. And to underline that directories are only the way of grouping within the file storage engine and thus not necessarily dirs.

Signed-off-by: Jelmer Schreuder <c32a429a36bda92253954f2812ae0f568a52ab52@mijnpraktijk.com>

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