#2215: add group in TOC toolbar

[mbarto]

Description

Improvements to the TOC:

• NEW add group button (when status is DESELECTED or a single group is selected)
• add layer button (when status is DESELECTED or a single group is selected) --> adds a layer directly to the selected group

Issues

• Fix Allow creation of new groups / subgroups from the TOC #2215

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: https://github.com/geosolutions-it/MapStore2/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x", remove the others)

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior? (You can also link to an open issue here)
Adding a new group or adding a layer to an existing group is complicated.

What is the new behavior?
Adding a new group or adding a layer to an existing group is easier.

Does this PR introduce a breaking change? (check one with "x", remove the other)

• Yes, and I documented them in migration notes
• No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: ...

Other information:

[coveralls]

Coverage decreased (-27.01%) to 54.398% when pulling 71b2235 on mbarto:add_groups into 410fb7d on geosolutions-it:master.

[offtherailz]

Here the things I noticed:

• When I delete a layer, all new groups are removed

• If I use a . (dot) as the name of the group (for instance geo-solutions.it), then I open the layer properties, the groups selector i see geo-solutions/it
  

• If a group is selected we are going to add the layer/group from the button as a sub-group. Maybe in this case the tooltip should show something like "add sub-group to the selected group" or "add layer to the selected group". Using the name of the group in the tooltip is a plus.

• Wrong tooltip for group properties
  

• Wrong tooltip for group visibility button (I verified this issue already exists on dev)
  

Here some things that may be confusing:

• When I open the catalog from the TOC the layer is added to the selected group, when I do it from the menu, the layer is added to the "Default" group. This may confuse the user.
• When I select a group to add layers to it, all it's layers in the group are selected, too. When I add a new layer to the selected group, this new layer is not selected. This looks somehow correct to me, but may be confusing. Just wanted to make you notice it.

This gif describes both layer selction and add from catalog issues:

[offtherailz]

Why not directly the object? I think is more explicit that the array:

setControlProperties('mycontrol', 'a', 1, 'b', 2); // less intuitive
setControlProperties('mycontrol', {a:1, b: 2}) // more intuitive

Notice. The documentation tells something different. I didn't try yet, but documenting spread operator may work using this syntax @param {...object} myParam (JSDoc 3.4.3). Please try (or refactor as suggested)

[mbarto]

Because using ...properties is more functional friendly (partial application) and in fact my first usage of it took advantage of partial application. Eventually we can also support both syntaxes

[offtherailz]

Now I see. That's cool 👍
I should not provide both to avoid confusion.

So you could one of the following:

1. Change the documentation to specify better how to use the action, maybe with an example
2. Make the properties an object and change all the .bind with something like

( properties ) => setControlProperties('myControl', {  {a: 1, b: 2}, ...properties} }

Do what you think is better.

[mbarto]

@offtherailz "When I open the catalog from the TOC the layer is added to the selected group, when I do it from the menu, the layer is added to the "Default" group. This may confuse the user."
What you suggest instead?

[offtherailz]

@mbarto I'd like to see the opinion of @tdipisa about it. Anyway I can suggest to set the tooltip "Add layer to the selected group", that clarifies a little bit. I think that it could be enough.

[offtherailz]

Good. Almost done
Please look at my comments (1 inline, 1 on PR) and try to solve translation file conflict