Add ALE integration

[MTDL9]

Add a custom ALE checker, defined when the plugin is loaded and ALE is installed on the local VIM, that will mark all errors and warnings in the log file (using the error and warning keywords) and populate the location list.

This will allow displaying all the errors and jumping to them quickly using the location list functions/keybindings.

Might require converting the syn keyword definitions used for log levels into configurable variables.