Codechange: refactor DecodeHexText to a generic purpose ConvertHexToBytes (#11866)

DecodeHexText() does more than just decoding hex. ConvertHexToBytes()
now only does pure hex decoding. This required a bit of refactoring
for the code using DecodeHexText().

Codechange: automatic adding of _t to (u)int types, and WChar to char32_t

for i in `find src -type f|grep -v 3rdparty/fmt|grep -v 3rdparty/catch2|grep -v 3rdparty/opengl|grep -v stdafx.h`; do sed 's/uint16& /uint16 \&/g;s/int8\([ >*),;[]\)/int8_t\1/g;s/int16\([ >*),;[]\)/int16_t\1/g;s/int32\([ >*),;[]\)/int32_t\1/g;s/int64\([ >*),;[]\)/int64_t\1/g;s/ uint32(/ uint32_t(/g;s/_uint8_t/_uint8/;s/Uint8_t/Uint8/;s/ft_int64_t/ft_int64/g;s/uint64$/uint64_t/;s/WChar/char32_t/g;s/char32_t char32_t/char32_t WChar/' -i $i; done

Cleanup: remove str_strip_colours; StrMakeValid also removes the colours

Essentially str_strip_colours followed by StrMakeValid makes the calling of
str_strip_colours useless, as StrMakeValid would have removed them too.

Change: [Network] Transfer command data as serialized byte stream without fixed structure.

The data will be transmitted as the length followed by the serialized data. This allows the command
data to be different for every command type in the future.

Codechange: move casting a "const char *" to "char *" to the caller

It is not nice to have your definition say you won't change a value
while in fact the whole reason for your existance is to change it.

Codechange: rename str_validate to StrMakeValid(InPlace) (#9304)

This to be more explicit the function changes the value, and not
returns yes/no.

Revert c1fddb9, 639cfa4: "Codechange: Check if access __attribute__ is supported before trying to use it." (#8526)

This reverts commit c1fddb9a6ae5c3af6865461a7295788a341011a2 and 639cfa43d23aa142cabbf2f08ec20a2133b0503e.

access_mode "none" is only supported by GCC11, but introduced
after it branched. So there are GCC11.0s out there that do not
support it. We will have to wait for GCC11.1 to hit before we
can re-add this.

(svn r16269) -Codechange: use gcc's ability to check parameters sent to printf-like functions
-Fix: wrong number of parameters or wrong parameter types sent to printf-like functions at several places

(svn r14546) -Codechange: Unify string(cpy|cat) functions
-Doc: string(cpy|cat) functions