Support non-native runtime builds

[gilesknap]

Allow use of ibek in cross compiled runtime targets by:

• changing extract runtime assets to not copy all the support and epics-base binaries (because cross compile is static)
• ignore calls to apt-install

cross compilation is identified by the environment vars EPICS_TARGET_ARCH != EPICS_HOST_ARCH

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 42.85714% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 72.63%. Comparing base (12d3826) to head (1cdd944). Report is 10 commits behind head on main.

:exclamation: Current head 1cdd944 differs from pull request most recent head 47f3d64. Consider uploading reports for the commit 47f3d64 to get more accurate results

Files	Patch %	Lines
src/ibek/ioc_cmds/assets.py	0.00%	9 Missing :warning:
src/ibek/support_cmds/commands.py	0.00%	3 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #186 +/- ## ========================================== - Coverage 73.14% 72.63% -0.51% ========================================== Files 17 17 Lines 890 910 +20 ========================================== + Hits 651 661 +10 - Misses 239 249 +10 ```

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