Revamp protect docs with new settings guide

Settings

Created a new settings page with every custom query parameter and setting you can add to protect. In the past most of these have lived in the MEV-Share page but (1) we are adding new mempool params that are not MEV-Share specific and need a good home, and (2) some of the MEV-Share settings like refunds also affect gas fee refunds so they should live at the top level
Added info on the new mempool params to the new settings page
Updated how we describe some of the existing settings (eg. clarify that the refund parameter affects gas fee refunds, not just mev share refunds)

Other polish

Updated some of the copy on the protect quick start and overview pages (eg. we had slightly different descriptions of the key benefits on each page, now they are the same)
Updated the title of the MEV-Share page to "MEV refunds" to be more consistent with gas fee refunds and because in the protect section of the docs we should be naming things based on user facing features not the underlying protocols (which have their own pages elsewhere)
Updated some of the copy in the MEV-Share page to be more readable and consistent with the gas fee refunds page
Deleted settings from MEV-Share page that have moved to the settings page, changed the examples we have on the MEV-Share page to focus on privacy configurations (which is specific to MEV refunds and worth calling out on this sub page)

If I feel inspired I might also expand on the now-reduced MEV refunds page to include sections like we have on the gas refunds page. I think this is enough for now though.

flashbots / flashbots-docs

Revamp protect docs with new settings guide #578