JavaScript: add binaries, fix octals, improve escapes & allow Non-ASCII identifiers

Summary:
**Changes:**

* Add binaries: `0b0101` [1]
* Fix octals: the format of octals supported is: `0o1717`, but the HlCOct rule is equivalent to `01717`. [1]
* Improve escapes [2]: HlCStringChar rule does not contain the exact escapes supported by JavaScript:
	* The reserved character escapes are `'"\bfnrtv0`. These are now highlighted in bold (itemData: "Reserved Char. Escape").
	* Hexadecimal escapes in JS only support 2 numbers: `\xNN`, but HlCStringChar admits 1 or 2.
	* The maximum value of octal escape is `\377` (255 in decimal). For example, when typing `\477`, it's only considered as an escape: `\47`.
	* Any character can be escaped (previously, in the templates, the special character "$" for substitutions is not escaped).
* In "JavaScript React" the context "Conditional Expression", which is unnecessary, is eliminated to simplify the code.

* Add identifiers with Non-ASCII characters [3], to avoid highlighting RegExp and numbers after non-ASCII characters. This also applies to the highlighting of objects, functions and JSON properties.

BUG: 393633

**References:**
* [1] Standard ECMA-262, ECMAScript 2015 Language Specification. [11.8.3] Numeric Literals: https://ecma-international.org/ecma-262/6.0/#sec-literals-numeric-literals
* [2] Standard ECMA-262, ECMAScript 2015 Language Specification. [11.8.4] String Literals: https://ecma-international.org/ecma-262/6.0/#sec-literals-string-literals
* [3] Valid JavaScript variable names in ES2015: https://mathiasbynens.be/notes/javascript-identifiers-es6

Reviewers: dhaumann, cullmann, #framework_syntax_highlighting

Reviewed By: cullmann, #framework_syntax_highlighting

Subscribers: kwrite-devel

Tags: #kate, #frameworks

Differential Revision: https://phabricator.kde.org/D13888