Pull request #3312: JSN: Unescape Text Processing

Pull request #3312: JSN: Unescape Text Processing

Merge in SNORT/snort3 from ~OSERHIIE/snort3:js_unescape to master

Squashed commit of the following:

commit 5e79a2a365a4b5b74670d4bfc6f94bcc35f3b2d6
Author: Oleksandr Serhiienko <oserhiie@cisco.com>
Date:   Fri Mar 18 20:39:48 2022 +0200

    utils: fix JS Normalizer benchmark build

commit 8b79a4adbc538ea1b6400486cbe1b82a5369d1af
Author: Oleksandr Serhiienko <oserhiie@cisco.com>
Date:   Fri Mar 4 22:05:17 2022 +0200

    http_inspect: add unescape text processing for Enhanced JS Normalizer

        * utils: decode %XX, %uXXXX, \uXX, \uXXXX, \xXX, \u{CHAR_CODE} escape sequences
        * utils: decode hexadecimal and decimal code points
        * utils: add support for unescape of universal sequences in identifiers,
          strings, template literals and regular expressions
        * utils: add support for unescape(), decodeURI(), decodeURIComponent() JavaScript
          functions
        * utils: add support for String.fromCharCode() JavaScript function
        * utils: add unit test coverage
        * utils: add benchmark test
        * http_inspect: enable alert 119:280 - mixed encoding
        * http_inspect: update dev notes
        * doc: update user manual