StorPool: support for direct download

[slavkap]

Description

Added support to download templates on StorPool directly

Types of changes

• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Bug fix (non-breaking change which fixes an issue)
• [X] Enhancement (improves an existing feature and functionality)
• [ ] Cleanup (Code refactoring and cleanup, that may add test cases)
• [ ] build/CI
• [ ] test (unit or integration test code)

Feature/Enhancement Scale

• [ ] Major
• [X] Minor

How Has This Been Tested?

Manually tested

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 127 lines in your changes missing coverage. Please review.

Project coverage is 15.78%. Comparing base (019f2c6) to head (b468ca4).

Files with missing lines	Patch %	Lines
...hypervisor/kvm/storage/StorPoolStorageAdaptor.java	0.00%	127 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #9833 +/- ## ============================================ - Coverage 15.78% 15.78% -0.01% Complexity 12564 12564 ============================================ Files 5627 5627 Lines 492250 492374 +124 Branches 61405 62914 +1509 ============================================ - Hits 77710 77709 -1 - Misses 406066 406191 +125 Partials 8474 8474 ``` | [Flag](https://app.codecov.io/gh/apache/cloudstack/pull/9833/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=apache) | Coverage Δ | | |---|---|---| | [uitests](https://app.codecov.io/gh/apache/cloudstack/pull/9833/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=apache) | `4.04% <ø> (ø)` | | | [unittests](https://app.codecov.io/gh/apache/cloudstack/pull/9833/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=apache) | `16.60% <0.00%> (-0.01%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=apache#carryforward-flags-in-the-pull-request-comment) to find out more.

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