GSLUX-753: Legend panel

[AlitaBernachot]

JIRA issue

https://jira.camptocamp.com/browse/GSLUX-753

Description

• New Legends panel
• refactor getMetadata and getLegend to be used in metadata opup and in legends panel
• add cache for getMetadata() (cache is cleared when language is changed)
• update chore dep i18next-vue to last release
• refactor app store => setters have been moved to new side-panel.vue component, now using watchers, allowing v3 to have its own custom behavior in MainController.js with both angular and vuejs' watchers, as this new side-panel is not yet in v3

[github-actions]

GitHub Pages links: * Luxembourg-geoportail: https://geoportail-luxembourg.github.io/luxembourg-geoportail/GSLUX-753-legends/

[tkohr]

Thanks for the various refactorings @AlitaBernachot ! Works as expected :-)

[tkohr]

Thanks for the refactoring! Maybe we could even put all these into one sidePanelOpen variable with predefined values defining its state in the future (not within this PR). WDYT?

[AlitaBernachot]

Do you mean something like :

const sidePanelOpen = ref({
layersOpen: true,
legendsOpen: true,
myMapsOpen: true,
...
})

I am not a big fan of this solution because it means when a component is linked to themeGridOpen property only (for example), it will also trigger a refresh when the other properties are changed.

[tkohr]

Yep, good point. I was rather thinking of something like:

type SidePanelOpenState = 'layersOpen' | 'legendsOpen' | ...
const sidePanelOpenState = ref<SidePanelOpenState>('layersOpen')

or maybe using an enum, but just as an idea for future refactoring...

[AlitaBernachot]

Oh! right! this is much better than what I thought. Well, why not :). I am merging this PR, feel free to improve this side panel state.