The AppData files provide descriptive data about an application, and is
typically used in application managers to display additional information to
the user. Having an AppData file is especially important for some graphical
application installers: without one, an application manager may not event
show an entry for the application. This happens for example in GNOME Software.

For the sake of completeness, this commit not only adds the AppData file to
the Flatpak build, but also to the Linux .deb and .rpm packages.

fixes #12845

Implement terminal.integrated.cwd

Fixes #17387

Part of #17331

Updates path completions for directories and files to use a file icon instead of the generic icon they currently use.

Fixes #16888

**Bug**
The js/ts completion provide can currently only complete whole words (as defined by `TextDocument.getWordRangeAtPosition`). This causes completion of literal string types to fail if they are not a whole word.

**Fix**
Instead of relaying on the default range, compute a range by taking the longest match of the replacement text from the current position.

Fixes #17232

Add a few niceties for making Flatpak builds of VSCode

Make high contrast detection configurable

Issue with saving files on mounted drive: "Could not resolve any model with provided uri" (fixes #17345)

When storing the output of a Flatpak build to a commit into an OSTree
repository (by setting the $FLATPAK_REPO environment variable), it is
good to have a descriptive subject in the commit log message.

This makes the Flatpak builds honor the $FLATPAK_REPO environment variable.
When it is defined, it will be used as the path to an OSTree repository where
the Flatpak application bundle will be committed to. This allows to place
multiple builds in the same repository (along other applications, even), which
can be published. For more details abuit using repositories for publishing,
check:

   http://flatpak.org/developer.html#Distributing_Applications

Note that setting $FLATPAK_REPO disables building a standalone .flatpak bundle
file.

This honors the following environment variables:

- $GPG_KEY_ID: When set, it can be the identifier, full fingerprint, or
  email address of a GnuPG key which will be used to sign Flatpak builds.

- $GPG_HOMEDIR: Path to an alternative home directory to be used by GnuPG,
  instead of the default ~/.gnupg directory of the current user. This can
  be used to point GnuPG to a different keychain.

related to #16639

Take code editor as argument instead of workbench editor
Option to decorate whole line or not