Panspermia intro text edit

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Brief Description of What This PR Does

The panspermia intro text (that I wrote) was a bit clumsy, so I wrote it again.

Related Issues

Progress Checklist

Note: before starting this checklist the PR should be marked as non-draft.

• PR author has checked that this PR works as intended and doesn't
  break existing features:
  https://wiki.revolutionarygamesstudio.com/wiki/Testing_Checklist
  (this is important as to not waste the time of Thrive team
  members reviewing this PR)
• Initial code review passed (this and further items should not be checked by the PR author)
• Functionality is confirmed working by another person (see above checklist link)
• Final code review is passed and code conforms to the
  styleguide.

Before merging all CI jobs should finish on this PR without errors, if
there are automatically detected style issues they should be fixed by
the PR author. Merging must follow our
styleguide.

[hhyyrylainen]

There was a bit of talk on the dev Discord but I don't think we came up with a real improved version on the current text in the game...

[github-actions]

This PR has been inactive for a while and as such is being marked
stale. This PR will be automatically closed if this stays stale
for a while.

If this is still being worked on / will probably resume work at
some point please feel free to continue working on this and reopen
this in case this was already automatically closed.