Adds hdl_checker LSP support (#2804)

* Added hdl_checker support
* Added hdl_checker tests

HDL Checker searches for files when no config file is found, which could lead to very long searches when the user is not really on a project setting

ale_linters/verilog/hdl_checker.vim

@@ -0,0 +1,5 @@
+" Author:      suoto <andre820@gmail.com>
+" Description: Adds support for HDL Code Checker, which wraps vcom/vlog, ghdl
+"              or xvhdl. More info on https://github.com/suoto/hdl_checker
+
+call ale#handlers#hdl_checker#DefineLinter('verilog')