Add project configuration and VHDL language server settings

vhdl_ls.toml

@@ -0,0 +1,16 @@
+[libraries]
+defaultlib.files = [
+    'tests/*.vhd',
+    'src/*.vhd',
+    'src/*/*.vhd',
+]
+
+# Libraries can be marked as third-party to disable some analysis warnings, such as unused declarations
+UNISIM.files = [
+    '/opt/Xilinx/14.7/ISE_DS/ISE/vhdl/src/unisims/unisim_VCOMP.vhd',
+]
+UNISIM.is_third_party = true
+
+[lint]
+unused = 'error' # Upgrade the 'unused' diagnostic to the 'error' severity
+unnecessary_work_library = false # Disable linting for the 'library work;' statement