Improve debugging utils

[aedart]

PR adds a new var_dump() function, which is now internally used by both dump() and dd().

Details

Consider the following example (taken from the docs):

set(my_str "Hi there")
set(my_empty_str "")
set(my_num 23)
set(my_float 1.1234)
set(my_bool true)
set(my_const on)
set(my_list "foo;bar;42;true")
set(my_cached_prop "My cached var..." CACHE STRING "Testing")
set(ENV{my_env_prop} "/home/other/place")

macro(my_macro)
endmacro()

function(my_function)
endfunction()

var_dump(PROPERTIES
    my_str
    my_empty_str
    my_num
    my_float
    my_const
    my_undefined_prop
    my_list
    my_cached_prop
    my_env_prop
    my_macro
    my_function
)

Outputs:

my_str = (string 8) "Hi there"
my_empty_str = (string 0) ""
my_num = (int) 23
my_float = (float) 1.1234
my_const = (string 2) "on"
my_undefined_prop = (undefined) 
my_list = (list 4) [ 
   0: (string 3) "foo"
   1: (string 3) "bar"
   2: (int) 42
   3: (bool) true
]
my_cached_prop = (string 4, cached) "Yolo"
my_env_prop = (string 17, ENV) "/home/other/place"
my_macro = (command) my_macro()
my_function = (command) my_function()

If ANSI is enabled, the output will be formatted / styled with colors. In addition, the var_dump() also supports a few options, which allows it to omit variable names, and treat lists as strings instead, if the default behavior isn't desirable.