Remove access to data from UI modules

[gogonzo]

Reason of this issue is that filter-panel UI can't be initialized without data. It's because filter_panel_ui is a part of FIlteredData class. We would like to initialize empty filter-panel and update it when the data is available.

Proposition

UI modules have access to data to initialize the inputs which messes up teal reactivity. Please do:

• FIlteredData$new() should initialize empty FilteredData with empty ui/srv_filter_panel
• FilteredData$set_filtered_dataset should create FilteredDataset and insert it into private$filtered_datasets (reactiveValues).
• All functions which refer to filtered_datasets will be then reactive on a change in reactiveValues
• UI should not have any connection to the data nor FilteredData (they shouldn't be the arguments of the function)
• UI should be initialized on the informations we have before data is available - datanames and maybe join keys
• The rest of the UI components should be either updated or rendered by server when reactive data is available (or changed).

This issue will require other actions which should be addressed in the same PR:

• Possibly we would like to exclude shiny modules from the classes.
• move calling UIs and servers to the module_nested_tabs. Feasible - please see the branch

[gogonzo]

I suggest to not address this issue at this moment (february 2023). PR I've made #185 shows how complex these modules are. Removing UI from the classes is confusing and not relevant at this moment of the refactor process. Issue is related more with the teal 1.0 milestone

[gogonzo]

Closing this up as it can be done under this issue insightsengineering/teal#669