Enhancement: [Search] Provide a way for users to see all tiers and prices for their current subscription

### Impacted plugin

Search

### What

Jetpack Search users should be able to see a list of all the tiers and prices for their current subscription, so they can understand what they might pay in the future and why.

### How

We used to provide a table of Search tiers and prices on [this page](https://jetpack.com/support/search/jetpack-search-product-billing/) and link to it from WordPress.com and Jetpack billing emails as a place to learn more about the price we are going to charge the user for their upcoming renewal. This was always imperfect, though (for example, it was in USD only) and has since been removed. Users can still see all the **current** tiers and prices (i.e., for a new purchase) via the slider at https://jetpack.com/upgrade/search/, but that's not necessarily what they are personally going to pay on a renewal because older subscriptions can and do pay different prices.

Example of how the loss of this feature can cause problems: p1HpG7-hSD-p2#comment-57058 and subsequent comments

The suggestion would be to surface the full list of tiers and prices for the current user's billing plan somewhere where they can access it (and then change the above documentation page to point them to it).

One possibility would be inside the Jetpack Search Record Meter, for example somewhere in here (or even behind the `(i)` icon):


Another possibility would be in the Calypso billing pages, since we already do show an accurate price for their **current** tier there (and could therefore link off to somewhere else that could show a dynamically-constructed list of all possible tiers and prices):


The proposed entry points are the Jetpack Search Record Meter and Calypso billing pages; begin by tracing where the current-tier price is displayed and how the user's billing plan is loaded. The issue does not name files or tests, and done would be a decided location that exposes every tier and renewal price for the current plan, with the documentation page linking to it.

Written by the indexing model from the issue text.