Buy NavCoin requires updating

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Description

Some exchanges listed do not have a NavCoin pair, and may require temporary removal while waiting for confirmation from the exchange.
It has been suggested that the exchange listings be categorised in terms of:
KYC / non KYC
Exchange / insta Exchange
and that the "buy-navcoin" page on the website reflect this.

Motivation

The "buy-navcoin" page is currently not accurate, and requires updating.

Acceptance Criteria

The page is made more accurate, and possibly reflects some of the elements in the description.

• Description is satisfied.
• Changes display correctly on desktop / mobile.
• Translations have been added or amended as necessary.