Restructure wiki to prepare for Helios64.

* Move all previous info into Helios4 subfolder
* Add helios64 subfolder
* Update all url link

Note: http server has been configure to ensure existing inbound link can 
still be resolved to the right page.

docs/helios4/files/dt-overlay/compile-dtb-lk-4.14.patch

@@ -0,0 +1,14 @@
+diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
+index aac94d96..d22bb79d 100644
+--- a/scripts/Makefile.lib
++++ b/scripts/Makefile.lib
+@@ -270,6 +270,9 @@ cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \
+ # ---------------------------------------------------------------------------
+ DTC ?= $(objtree)/scripts/dtc/dtc
+ 
++# Enable overlay support
++DTC_FLAGS += -@
++
+ # Disable noisy checks by default
+ ifeq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
+ DTC_FLAGS += -Wno-unit_address_vs_reg \

docs/helios4/files/dt-overlay/compile-dtb-lk-4.19.patch

@@ -0,0 +1,14 @@
+diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
+index 61e596650..fdb066e51 100644
+--- a/scripts/Makefile.lib
++++ b/scripts/Makefile.lib
+@@ -244,6 +244,9 @@ cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \
+ # ---------------------------------------------------------------------------
+ DTC ?= $(objtree)/scripts/dtc/dtc
+ 
++# Enable overlay support
++DTC_FLAGS += -@
++
+ # Disable noisy checks by default
+ ifeq ($(findstring 1,$(KBUILD_ENABLE_EXTRA_GCC_CHECKS)),)
+ DTC_FLAGS += -Wno-unit_address_vs_reg \