manuals: replace "apt-get" by "apt"

Modern Debian based distros (such as Ubuntu) now
use "apt" instead of "apt-get"

Also make sure "apt" is invoked with root privileges (mandatory)

(From yocto-docs rev: 380ef2474f3ecc2bce83f11cd838d054bef56d22)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Reviewed-by: Quentin Schulz <foss@0leil.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/brief-yoctoprojectqs/index.rst

@@ -80,7 +80,7 @@ distribution:
 
 .. code-block:: shell
 
-  $ sudo apt-get install &UBUNTU_HOST_PACKAGES_ESSENTIAL;
+  $ sudo apt install &UBUNTU_HOST_PACKAGES_ESSENTIAL;
 
 .. note::
 

documentation/dev-manual/common-tasks.rst

@@ -5874,7 +5874,7 @@ system image files much faster.
       use the tool without specifying ``PATH`` even from the root
       account::
 
-         $ sudo apt-get install bmap-tools
+         $ sudo apt install bmap-tools
 
    -  If you are unable to install the ``bmap-tools`` package, you will
       need to build Bmaptool before using it. Use the following command::
@@ -7066,7 +7066,7 @@ to fetch the repository information:
 
 .. code-block:: none
 
-  # apt-get update
+  $ sudo apt update
 
 After this step,
 ``apt`` is able to find, install, and upgrade packages from the
@@ -8249,7 +8249,7 @@ might be significant in human-readable form. Here is an example::
 
 
    Alternatively, you can install ``python3-git`` using the appropriate
-   distribution package manager (e.g. ``apt-get``, ``dnf``, or ``zipper``).
+   distribution package manager (e.g. ``apt``, ``dnf``, or ``zipper``).
 
 To see changes to the build history using a web interface, follow the
 instruction in the ``README`` file

documentation/ref-manual/system-requirements.rst

@@ -120,23 +120,23 @@ supported Ubuntu or Debian Linux distribution:
       its own custom ``/usr/include/linux/soundcard.h`` on the Debian
       system. If you run into this situation, try either of these solutions::
 
-         $ sudo apt-get build-dep qemu
-         $ sudo apt-get remove oss4-dev
+         $ sudo apt build-dep qemu
+         $ sudo apt remove oss4-dev
 
    -  For Debian-8, ``python3-git`` and ``pylint3`` are no longer
-      available via ``apt-get``.
+      available via ``apt``.
       ::
 
          $ sudo pip3 install GitPython pylint==1.9.5
 
 -  *Essentials:* Packages needed to build an image on a headless system::
 
-      $ sudo apt-get install &UBUNTU_HOST_PACKAGES_ESSENTIAL;
+      $ sudo apt install &UBUNTU_HOST_PACKAGES_ESSENTIAL;
 
 -  *Documentation:* Packages needed if you are going to build out the
    Yocto Project documentation manuals::
 
-      $ sudo apt-get install make python3-pip
+      $ sudo apt install make python3-pip
       &PIP3_HOST_PACKAGES_DOC;
 
    .. note::

documentation/toaster-manual/setup-and-use.rst

@@ -211,7 +211,7 @@ Be sure you meet the following requirements:
 
 -  If you are using Ubuntu, run the following::
 
-      $ sudo apt-get install apache2 libapache2-mod-wsgi-py3 mysql-server python3-pip libmysqlclient-dev
+      $ sudo apt install apache2 libapache2-mod-wsgi-py3 mysql-server python3-pip libmysqlclient-dev
 
 -  If you are using Fedora or a RedHat distribution, run the
    following::

documentation/toaster-manual/start.rst

@@ -18,7 +18,7 @@ to run the Yocto Project. To do this, follow the instructions in the
 the Yocto Project Development Tasks Manual. For Ubuntu/Debian, you might
 also need to do an additional install of pip3. ::
 
-   $ sudo apt-get install python3-pip
+   $ sudo apt install python3-pip
 
 Establishing Toaster System Dependencies
 ========================================