Added support for /prompt - rebased

[aurelienaws]

Issue #, if available:
Initial PR #1055
Description of changes:
New PR after rebase.

This PR implements a new /prompt command allowing the use of pre-saved prompts stored locally (~/.aws/amazonq/prompts as per the IDE plugin).

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 22.95082% with 47 lines in your changes missing coverage. Please review.

Project coverage is 13.96%. Comparing base (e42f218) to head (25ba171).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/q_cli/src/cli/chat/mod.rs	6.12%	44 Missing and 2 partials ⚠️
crates/q_cli/src/cli/chat/command.rs	91.66%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1224   +/-   ##
=======================================
  Coverage   13.96%   13.96%           
=======================================
  Files        2365     2365           
  Lines      204847   204907   +60     
  Branches   185211   185271   +60     
=======================================
+ Hits        28604    28617   +13     
- Misses     174837   174882   +45     
- Partials     1406     1408    +2     

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[hayemaxi]

Please push rebases to the original PRs instead of making a new one