Remove rebornix.Ruby extension (devcontainers#737)

Remove the deprecated rebornix.Ruby extension from the list of installed extensions.

Update Features - Remove use of get_common_setting (devcontainers#735)

Update Features - Remove use of get_common_setting (devcontainers#735)

Update Features - Remove use of get_common_setting (devcontainers#735)

Update Features - Remove use of get_common_setting (devcontainers#735)

[common-utils] Bug fix: zsh missing rc snippet (devcontainers#736)

* [common-utils] Bug fix: zsp missing rc snippet

* condion rc snippet

* fix bug

* remove debugging step

Update Features - Remove use of get_common_setting (devcontainers#735)

Update Features - Remove use of get_common_setting (devcontainers#735)

Add PowerShell extension (devcontainers#731)

* Add PowerShell extension

* Bump feature version

Try connecting to Ubuntu keyserver on port 80 if default HKP port fai…

…ls (devcontainers#722)

* Try Ubuntu keyserver on port 80 if default HKP port fails

Closes devcontainers#719
Closes devcontainers#717

* Bump feature versions

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Co-authored-by: Samruddhi Khandale <skhandale@microsoft.com>