Add CMake linter cmake-lint (#4036)

* Add CMake linter cmake-lint

Add support for the CMake linter provided by
https://github.com/cheshirekow/cmake_format.

* Escape cmake-lint executable and add linter tests

test/handler/test_cmake_lint_handler.vader

@@ -0,0 +1,30 @@
+Before:
+  runtime ale_linters/cmake/cmake_lint.vim
+
+After:
+  Restore
+
+  call ale#linter#Reset()
+
+Execute(The cmake_lint handler should handle basic warnings):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 126,
+  \     'col': 0,
+  \     'type': 'W',
+  \     'code': 'C0301',
+  \     'text': 'Line too long (136/80)',
+  \   },
+  \   {
+  \     'lnum': 139,
+  \     'col': 4,
+  \     'type': 'W',
+  \     'code': 'C0113',
+  \     'text': 'Missing COMMENT in statement which allows it',
+  \   },
+  \ ],
+  \ ale_linters#cmake#cmake_lint#Handle(1, [
+  \   'CMakeLists.txt:126: [C0301] Line too long (136/80)',
+  \   'CMakeLists.txt:139,04: [C0113] Missing COMMENT in statement which allows it',
+  \ ])

test/linter/test_cmake_cmake_lint.vader

@@ -0,0 +1,13 @@
+Before:
+  call ale#assert#SetUpLinterTest('cmake', 'cmake_lint')
+
+After:
+  call ale#assert#TearDownLinterTest()
+
+Execute(The default command should be correct):
+  AssertLinter 'cmake-lint', ale#Escape('cmake-lint') . '  %t'
+
+Execute(The executable should be configurable):
+  let g:ale_cmake_cmake_lint_executable = 'foobar'
+
+  AssertLinter 'foobar', ale#Escape('foobar') . '  %t'