Rename jerry-port.h to jerryscript-port.h (#1762)

All public headers should follow the pattern `jerryscript[-*].h`.
The `jerry-api.h` to `jerryscript.h` renaming has already happened
a while ago, now it's time for the port API header to follow.

This patch
* renames the public header file,
* updates all includes to use the new file name (in `jerry-main`,
  in all the targets, and in the docs), and
* keeps `jerry-port.h` as a deprecated forwarding header to leave
  some time for external users to follow up with this change.

As a related change, the header of the default port implementation
is also changed to `jerryscript-port-default.h`.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

docs/05.PORT-API.md

@@ -116,7 +116,7 @@ This section describes a basic port implementation which was created for Unix ba
 
 ```c
 #include <stdlib.h>
-#include "jerry-port.h"
+#include "jerryscript-port.h"
 
 /**
  * Default implementation of jerry_port_fatal.
@@ -131,7 +131,7 @@ void jerry_port_fatal (jerry_fatal_code_t code)
 
 ```c
 #include <stdarg.h>
-#include "jerry-port.h"
+#include "jerryscript-port.h"
 
 /**
  * Provide console message implementation for the engine.
@@ -168,7 +168,7 @@ jerry_port_log (jerry_log_level_t level, /**< log level */
 
 ```c
 #include <sys/time.h>
-#include "jerry-port.h"
+#include "jerryscript-port.h"
 
 /**
  * Default implementation of jerry_port_get_time_zone.