Docs: Update Debian & Ubuntu install prerequisites

Latest versions of apt-get don't install as much packages by default
as older ones. This fix adds some missing packages discovered for an OS
derived from the latest stable Debian. These packages exist for older
Debian derivatives as well (tested with Ubuntu 16.04 LTS).

Closes https://github.com/espressif/esp-idf/issues/4480

docs/en/get-started-cmake/linux-setup-scratch.rst

@@ -19,7 +19,7 @@ To compile with ESP-IDF you need to get the following packages:
 
 - Ubuntu and Debian::
 
-    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache
+    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache libffi-dev libssl-dev
 
 - Arch::
 

docs/en/get-started-cmake/linux-setup.rst

@@ -17,7 +17,7 @@ To compile with ESP-IDF you need to get the following packages:
 
 - Ubuntu and Debian::
 
-    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache
+    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache libffi-dev libssl-dev
 
 - Arch::
 

docs/en/get-started/linux-setup-scratch.rst

@@ -14,7 +14,7 @@ To compile with ESP-IDF you need to get the following packages:
 
 - Ubuntu and Debian::
 
-    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing
+    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing libffi-dev libssl-dev
 
 - Arch::
 

docs/en/get-started/linux-setup.rst

@@ -14,7 +14,7 @@ To compile with ESP-IDF you need to get the following packages:
 
 - Ubuntu and Debian::
 
-    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing
+    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing libffi-dev libssl-dev
 
 - Arch::
 

docs/zh_CN/get-started-cmake/linux-setup-scratch.rst

@@ -19,7 +19,7 @@
 
 - Ubuntu 和 Debian::
 
-    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache
+    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache libffi-dev libssl-dev
 
 - Arch::
 

docs/zh_CN/get-started-cmake/linux-setup.rst

@@ -17,7 +17,7 @@ Linux 平台工具链的标准设置 (CMake)
 
 - Ubuntu 和 Debian::
 
-    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache
+    sudo apt-get install git wget libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing cmake ninja-build ccache libffi-dev libssl-dev
 
 - Arch::
 

docs/zh_CN/get-started/linux-setup-scratch.rst

@@ -15,7 +15,7 @@
 
 - Ubuntu 和 Debian::
 
-    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing
+    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing libffi-dev libssl-dev
 
 - Arch::
 

docs/zh_CN/get-started/linux-setup.rst

@@ -16,7 +16,7 @@ Linux 平台工具链的标准设置
 
 - Ubuntu and Debian::
 
-    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing
+    sudo apt-get install gcc git wget make libncurses-dev flex bison gperf python python-pip python-setuptools python-serial python-cryptography python-future python-pyparsing libffi-dev libssl-dev
 
 - Arch::