Implement `sorting-members` lint rule for class member ordering

[FMorschel]

Based on the idea from member-ordering.

Implement a lint rule named sorting-members to enforce a consistent order of class members as specified in the configuration. This rule should support customizable member ordering and optional alphabetization.

Supported optional modifiers (must be used in the idiomatic order - below):

overridden- (fields, methods, getters/setters) - excludes static-
external- (all members) - excludes abstract-
abstract- (fields and methods) - excludes static- and late- - when not external-
static- (fields, methods, getters/setters) - when not overridden-
late- (fields only) - when not abstract- or external-
var-, final-, or const- (fields only)
nullable- (all members)
operator- (methods only)
initialized- (fields only)
const- (constructors only)
factory- (constructors only)
named- (constructors only)
redirecting- (constructors only)
public- or private- (all members)

Supported groups (required, must be last):

fields
getters
getters-setters
setters
field-getter-setter
constructors
methods

Valid config entry format:

[modifier-]*group

[FMorschel]

Blocked by dart-lang/sdk#61755.

[FMorschel]

This is partially implemented. With #5, we can now add an annotation to all classes we want to sort. It is a bit more cumbersome, but at least doable while the ideal format is not available.