ATL-1118: Add keymaps customization support

[fstasi]

The default keybindings may be reasonable for beginners, but PRO users expect the keybindings to be customizable, as they are in other editors.

In this PR:

• add the theia/keymap packages that let users change the default keybindings to their preference (see image below)

• refactor the settings menu: from a single entry it's now submenu containing both the settings and the keymap actions to open the relevant functionalities (see images below)

(window version)

[kittaakos]

I wonder if the Settings name is appropriate here when the window title shows Preferences

and it is Preferences in the Java IDE:

What is the current policy? In the past, keeping the Java IDE UI/UX was a rule of thumb? Thanks!

[kittaakos]

It works nicely and the code looks good 👍

Please wait for another verification before the merge. Thanks!

[fstasi]

It works nicely and the code looks good 👍

Please wait for another verification before the merge. Thanks!

adding @ubidefeo for a double check before merging

[ubidefeo]

I have only one problem with this, and it's the placement of the key-bindings as a sub-menu of "preferences".
Historically the IDE preferences menu item served as an item, not a container of sub-options.
When a new user reads "go to ... > preferences" they won't know wether settings or key-bindings is the place to go.
@giannicolab @per1234 what's your take on this?

[per1234]

My concern with the new menu structure is that it breaks all the documentation/tutorials/etc. that tell people to open File > Preferences.

My preference would be to have the keyboard shortcut editor accessed via the File > Preferences dialog. But I'm guessing this is simply not technically feasible. So I'm thinking the best approach is to leave the File > Preferences menu path alone and add a new menu item for the keyboard shortcuts.

I think it's really nice to have configurable keyboard shortcuts. This is a feature I always look for in the applications I use.

[fstasi]

@per1234 @giannicolab @ubidefeo updated as below

[per1234]

Thanks Francesco!