fix(android): keyboard's black bar bug

refactor(web): overhaul of OSK key layout calcs + styling, merges desktop & touch logic 📐

refactor(web): reworks VisualKeyboard layout spec design 📐

refactor(web): OSK layout hierarchy encapsulation 📐 

feat(ios): adds option for Simulator-compatible testing artifact

feat(web): setup build artifacts for manual tests

This is work arising from the spacebarText postmortem. The only changes
in this commit at present are in the readme, just to give us a pull
request to play with.

chore(common/core): Add uninstall option to build script

docs(linux): Fix readme for ibus-keyman

Co-authored-by: Marc Durdin <marc@durdin.net>

auto: increment master version to 15.0.96

chore(common/core): Linux side of caps-lock stores 🚧

Turns out setting `KEYMAN_PROC_CFLAGS` isn't sufficient to use header
files from source repo.

This change improves capslock handling with a capsAlwaysOff keyboard.
Previously, the caps lock indicator was turned on while holding down
the Caps Lock key. With this change we turn it off immediately. This
is done by forcing caps lock off even if the state already seems to
match.

Also, for capsAlwaysOff keyboards skip further processing of caps
lock key after we turned capslock off again.

chore(linux): Consolidate Debian source packages 📦

This change adds a virtual package `keyman-engine` which ibus-keyman
provides. keyman-config can then depend on this virtual package.
This allows to use fcitx instead of ibus if the fcitx-keyman package
provides that virtual package as well.

The previous commit created a consolidated toplevel `debian`
directory.

This change consolidates the Debian packages into a single source
package, with the exception of the legacy KMFL packages.

Fixes #5022.

fix(web): Blank spacebar text when displayName is empty string

fix(common/models): keep/suggestion diacritic sensitivity when de-duping

feat(developer): debugger uses Keyman Core 🐞

fix(common/core/desktop): split smp for context chars

fix(android/app): Fix cleanup when progress dialog cancelled

feat(android): Add API for checking Chrome version

Fixes #5465.
Fixes #5561.

If a non-BMP Unicode char was emitted into the internal context, it was
being truncated to a WORD, which caused data loss for multi-group
keyboards.

Includes an update to a unit test to validate this fix.