add orderly_packages method

[hillalex]

Add new utility orderly::orderly_packages() to return a list of required packages to run all reports in an orderly source.

[codecov]

Codecov Report

Merging #326 (49cc745) into master (d02fc85) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 49cc745 differs from pull request most recent head d17c640. Consider uploading reports for the commit d17c640 to get more accurate results

@@           Coverage Diff           @@
##           master     #326   +/-   ##
=======================================
  Coverage   99.95%   99.95%           
=======================================
  Files          41       41           
  Lines        4535     4546   +11     
=======================================
+ Hits         4533     4544   +11     
  Misses          2        2           

Impacted Files	Coverage Δ
R/info.R	100.00% <100.00%> (ø)
R/query_search.R	100.00% <100.00%> (ø)

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[hillalex]

The buildkite/orderly/pr check is failing because of a flaky selenium test in the downstream orderlyweb build. But I don't have any insight about the failing check-orderly-server check? Logs here: https://github.com/vimc/orderly.server/actions/runs/4500508760

[ubuntu-20.04 (release)](https://github.com/vimc/orderly.server/actions/runs/4500508760/jobs/7919727136#step:12:138)
'worker_spawn' is not an exported object from 'namespace:rrq'