adding "Google Translate" into context menu when right clicking website

[kjozwiak]

Description

As per @BrendanEich, we should see if we can add the "Google Translate" extension capability to into the context menu so a user can TRANSLATE THIS PAGE by simply right clicking anywhere on the page rather than going through the extension icon.

The "Google Translate" icon does appear in the context menu in the following scenarios:

Right clicking on links*

You'll also get a "Google Translate" button when selecting text as per the following:

Steps to Reproduce

1. visit https://www.spiegel.de and right click the page

Actual result:

Expected result:

We should see if it's possible to add the "Google Translate" into the context menu when right clicking on pages so users can translate the page quicker without needing to click on the extension.

Reproduces how often:

100% reproducible when going through the above STR.

Brave version (brave://version info)

Brave | 1.5.115 Chromium: 80.0.3987.149 (Official Build) (64-bit)
-- | --
Revision | 5f4eb224680e5d7dca88504586e9fd951840cac6-refs/branch-heads/3987_137@{#16}
OS | macOS Version 10.15.3 (Build 19D76)

Brave | 1.7.76 Chromium: 80.0.3987.149 (Official Build) dev (64-bit)
-- | --
Revision | 5f4eb224680e5d7dca88504586e9fd951840cac6-refs/branch-heads/3987_137@{#16}
OS | macOS Version 10.15.3 (Build 19D76)

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the dev channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? N/A
• Does the issue resolve itself when disabling Brave Rewards? N/A
• Is the issue reproducible on the latest version of Chrome? N/A

Miscellaneous Information:

CCing @rebron @bsclifton @BrendanEich