Unifying locale into single json file

[hakasapl]

Currently, the website's locale is spread out throughout the site in the form of a central en.php, or hardcoded on various pages of the site. We should combine all of these strings into the json file resources/locale/en.json. The format of the json file should be as follows:

{
    "<section>": {
        "string_name": "This is a string",
        "custom_string_name": "This is a string which has ${VAR} as parameter"
    }
}

Then, this file must be read by php using the json_decode function (be sure to pass true on the second argument for associative array). We can then access the strings like config::locale["section"]["string_name"], and we can use str_replace to fill in any mid-string parameters.