fix(toolkit-lib): unnecessary dependency on promptly

[mrgrain]

Fixes #396

This PR refactors the resource import prompts to use the IoHost instead. With that change, we can remove the promptly library as a toolkit-lib dependency and only have it in the CLI.

The change itself is not in a code path that is currently publicly available to toolkit-lib users, it only affects the cdk import command. The user experience for this is virtually unchanged, see screenshots.

Before:

After:

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 78.71%. Comparing base (841bc03) to head (52f9eec).

Files with missing lines	Patch %	Lines
packages/aws-cdk/lib/cli/io-host/cli-io-host.ts	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #523      +/-   ##
==========================================
- Coverage   78.72%   78.71%   -0.01%     
==========================================
  Files          46       46              
  Lines        6974     6977       +3     
  Branches      772      773       +1     
==========================================
+ Hits         5490     5492       +2     
- Misses       1465     1466       +1     
  Partials       19       19              

Flag	Coverage Δ
suite.unit	78.71% <75.00%> (-0.01%)	⬇️

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