update: switch from 30-day trial to 1000 credit, 30-day trial

[solugebefola]

Describe your changes

Updates to references of the 30-day free trial. Now they refer to the $500 credits for the trial

Fixes BIZX-951

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[github-actions]

Allow 10 minutes from last push for the staging site to build. If the link doesn't work, try using incognito mode instead. For internal reviewers, check web-documentation repo actions for staging build status. Link to build for this PR: http://docs-dev.timescale.com/docs-update-switch-to-credit-trial-v1

[solugebefola]

@atovpeko I don't know if we want to substitute some of these references with variables, in case we want to change the amount of credits or the duration of the trial in the future?

[solugebefola]

OK, I just got word that we are going to release with $1000 in credits (point proven). Can we swap out a variable for the credit amount?

[atovpeko]

@solugebefola sure, will do the variable. Thanks!