create a flag to enblae/disable Vercel log drain usage for API routes

[dasfmi]

as Per the comment below:

In light of the recent, rather blatant, pricing changes at Vercel, wouldn't it make more sense to send as much as possible directly to Axiom and as little as possible via log drains?

from #184 (comment)

Current behavior:

next-axiom detected if Vercel integration is enabled. For API Routes, it will use console.log() to send logs to the Vercel log drain. This would improve performance and not wait for the logger to flush.

Expected behavior:

As Vercel log drain is not free anymore and getting expenseive, next-axiom should give the user an option to enable/disable usage of Vercel log drain in API routes and by-default send logs directly to Axiom.