Wget and curl both do the same thing. Remove wget and use only curl.

I noticed that we ask users to install both `wget` and `curl`. This feels redundant.

Signed-off-by: Arjo Chakravarty <arjo129@gmail.com>

Author: arjo129

harmonic/install_ubuntu_src.md

@@ -24,7 +24,7 @@ cases where the default option cannot be easily changed.
 Install tools needed by this tutorial:
 
 ```bash
-sudo apt install python3-pip wget lsb-release gnupg curl
+sudo apt install python3-pip lsb-release gnupg curl
 ```
 
 ## vcstool and colcon from pip
@@ -93,7 +93,7 @@ All the sources of gazebo-harmonic are declared in a yaml file. Download
 it to the workspace:
 
 ```bash
-wget https://raw.githubusercontent.com/gazebo-tooling/gazebodistro/master/collection-harmonic.yaml
+curl -O https://raw.githubusercontent.com/gazebo-tooling/gazebodistro/master/collection-harmonic.yaml
 ```
 
 Use `vcstool` to automatically retrieve all the Gazebo libraries sources from
@@ -114,7 +114,7 @@ method to install software dependencies.
 Add `packages.osrfoundation.org` to the apt sources list:
 
 ```bash
-sudo wget https://packages.osrfoundation.org/gazebo.gpg -O /usr/share/keyrings/pkgs-osrf-archive-keyring.gpg
+sudo curl https://packages.osrfoundation.org/gazebo.gpg -O /usr/share/keyrings/pkgs-osrf-archive-keyring.gpg
 echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/pkgs-osrf-archive-keyring.gpg] http://packages.osrfoundation.org/gazebo/ubuntu-stable $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/gazebo-stable.list > /dev/null
 sudo apt-get update
 ```