Translation team pages: Copy changes for a locale with no General Translation Editors.

[petya]

The current translation team pages have the following copy if there are no GTEs or PTEs added to the Rosetta site:

[Locale name] does not have any validators yet.

Since we don't use the term "validator" anymore, could we please change that text to:

[Locale name] does not have General and Project translation editors yet.

Here's a link to a page like that: ​https://make.wordpress.org/polyglots/teams/?locale=es_CR

Can we also change the "getting involved" link text from

Become a translator yourself, check if [Language name] needs some help!

to

Is this a language that you speak? Join the WordPress translation team for [Language name]

[coffee2code]

In 5160:

WP i18n teams: Change text on translation team pages.

• Replace "validators" with "General and Project translation editors"
• Replace all of the getting involved link text

Props SergeyBiryukov, petya.
Fixes #2588.