Add support for various debian source files (debian/{tests/control,control,copyright,watch,upstream/metadata}) (#5107)

* Add debian-lsp support for autopkgtest files

Add Language Server Protocol support for debian/tests/control files
using debian-lsp (https://github.com/jelmer/debian-lsp).

Vim detects these files as filetype 'autopkgtest' by default.

* Add debian-lsp support for debcontrol files

Add Language Server Protocol support for debian/control files using
debian-lsp (https://github.com/jelmer/debian-lsp).

debian-lsp provides diagnostics, completions, and code actions for
Debian package control files.

* Add debian-lsp support for debcopyright files

Add Language Server Protocol support for debian/copyright files using
debian-lsp (https://github.com/jelmer/debian-lsp).

* Add debian-lsp support for debchangelog files

Add Language Server Protocol support for debian/changelog files using
debian-lsp (https://github.com/jelmer/debian-lsp).

* Add debian-lsp support for debsources files

Add Language Server Protocol support for debian/source/format files
using debian-lsp (https://github.com/jelmer/debian-lsp).

* Add debian-lsp support for debupstream files

Add Language Server Protocol support for debian/upstream/metadata
files using debian-lsp (https://github.com/jelmer/debian-lsp).

Note: Vim does not detect debian/upstream/metadata files by default.
Users need to add filetype detection to their vimrc:

  autocmd BufNewFile,BufRead */debian/upstream/metadata setfiletype debupstream

* Add debian-lsp support for debwatch files

Add Language Server Protocol support for debian/watch files using
debian-lsp (https://github.com/jelmer/debian-lsp).

Note: Vim does not detect debian/watch files by default. Users need to
add filetype detection to their vimrc:

  autocmd BufNewFile,BufRead */debian/watch setfiletype debwatch

* Add debian-lsp to supported tools documentation

Update supported-tools.md, ale-supported-languages-and-tools.txt,
and ale.txt table of contents to include the new Debian filetype
linters (autopkgtest, debchangelog, debcontrol, debcopyright,
debsources, debupstream, debwatch).

test/test-files/debcontrol/debian/control

@@ -0,0 +1,12 @@
+Source: example
+Section: misc
+Priority: optional
+Maintainer: Example <example@example.com>
+Build-Depends: debhelper-compat (= 13)
+Standards-Version: 4.6.0
+
+Package: example
+Architecture: all
+Depends: ${misc:Depends}
+Description: Example package
+ This is an example package.