Remove ddev script from datadog_checks_dev

[swang392]

What does this PR do?

Remove ddev script from datadog_checks_dev. The new CLI package provides that and therefore this is a duplicate that can potentially cause conflicts

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached
• If the PR doesn't need to be tested during QA, please add a qa/skip-qa label.

[github-actions]

Test Results

    2 files      2 suites   7m 47s ⏱️
424 tests 424 ✔️   0 💤 0 ❌
848 runs  830 ✔️ 18 💤 0 ❌

Results for commit adea9a3.

[codecov]

Codecov Report

Merging #14837 (adea9a3) into master (b5e51ff) will not change coverage.
The diff coverage is n/a.

Flag	Coverage Δ
datadog_checks_dev	82.70% <ø> (ø)

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