DOC-1048: Update Kafka credentials to medium tier template

[freakwriter]

Removed prerequisites section, converted bullet points to more detailed numbered instructions.

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Overall readability score: 43.03 (🟢 +0.02)

File	Readability
kafka.md	50.72 (🟢 +18.2)

View detailed metrics

🟢 - Shows an _increase_ in readability 🔴 - Shows a _decrease_ in readability File | Readability | FRE | GF | ARI | CLI | DCRS --- | --- | --- | --- | --- | --- | --- [kafka.md](https://github.com/n8n-io/n8n-docs/blob/1b24b61fc4e6a558db00be4f6cb91ec0b43bc2df/docs/integrations/builtin/credentials/kafka.md "docs/integrations/builtin/credentials/kafka.md") | 50.72 | 34.32 | 9.16 | 13.4 | 14.83 | 7.95   | 🟢 +18.2 | 🟢 +22.64 | 🟢 +0.61 | 🟢 +3.2 | 🟢 +3.87 | 🟢 +1.03 Averages:   | Readability | FRE | GF | ARI | CLI | DCRS --- | --- | --- | --- | --- | --- | --- Average | 43.03 | 34.77 | 11.68 | 14.89 | 14.37 | 8.55   | 🟢 +0.02 | 🟢 +0.02 | 🟢 +0 | 🟢 +0 | 🟢 +0 | 🟢 +0

View metric targets

Metric | Range | Ideal score --- | --- | --- Flesch Reading Ease | 100 (very easy read) to 0 (extremely difficult read) | 60 Gunning Fog | 6 (very easy read) to 17 (extremely difficult read) | 8 or less Auto. Read. Index | 6 (very easy read) to 14 (extremely difficult read) | 8 or less Coleman Liau Index | 6 (very easy read) to 17 (extremely difficult read) | 8 or less Dale-Chall Readability | 4.9 (very easy read) to 9.9 (extremely difficult read) | 6.9 or less