add I2P function-enabling extension to Firefox profile

This MR adds the I2P in Private Browsing extension for this Firefox Profile Bundle installed on Windows. In the profile bundle, this will behave in the following ways:

• It will not override default Proxy Preferences for default container tabs(firefox-default cookie store) which means that the about:config proxy settings will remain in effect. I call this mode "Non-Brave-Like Mode" which refers to the fact that the proxy remains in use for all tabs.
• It will not be able to automatically override media.peerconnection about:config settings, leaving our user.js settings intact. It simply cannot override these settings from within the extension, to my knowledge. In order to enable webRTC over a proxy(disable_non_proxied_udp) media.peerconnection preferences will need to be removed from user.js. I'm not convinced we should do this just yet in i2p.firefox.
• It will add pageActions for HTTPS-over-I2P and X-I2P-Location information. It will add a search engine option(yacy.idk.i2p) in the browserAction panel.
• It will add bookmarks for each of the default I2P applications to the bookmarks toolbar.
• It will add a sidebar panel to Firefox which can be used as a minimal router console.
• It will automatically route I2P sites to their own container tab(firefox-container-6 cookie store). Sites and site-data from the I2P container will be wiped from the history and the local cache when directed to. This functionality is implemented independently of the browser's own "Private Browsing" mode. This cookie store is not accessible from firefox-default, nor the reverse.
• It will automatically route I2P application webUI's to their own container tabs(With separate cookiestores), and pin those tabs to the front of the tab order. These cookie stores are not accessible from firefox-default, firefox-container-6, or eachother
• It will handle magnet links within I2P if another handler isn't present.
• It will automatically configure itself for i2pcontrol and snark-rpc if they are present.