New field related to a node (folder) in the layer tree.

[RicardCots]

Is your feature request related to a problem? Please describe.
Adds a new field in the SITMUN database to specify the behavior of a folder node in the SITMUN viewer layer tree. False by default, when true all contained layers are loaded when (the user) clicks on the layer title (in the SITMUN viewer).

Describe the solution you'd like
A new filed named 'loaddata' or something similar, set false by default. A 'true' value indicates that a click on the folder title loads all the layers within that folder.

Describe alternatives you've considered
No alternatives considered

Additional context
No context required.

[fjlopez]

Done!