Adding recount3

[Ishikaarora13]

recount3 is for retrieving harmonized data of TCGA and GTEx.

FOR CONTRIBUTOR:

• I have read the CONTRIBUTING.md document and this tool is appropriate for the tools-iuc repo.
• License permits unrestricted use (educational + commercial)
• This PR adds a new tool or tool collection
• This PR updates an existing tool or tool collection
• This PR does something else (explain below)

There are two labels that allow to ignore specific (false positive) tool linter errors:

• skip-version-check: Use it if only a subset of the tools has been updated in a suite.
• skip-url-check: Use it if github CI sees 403 errors, but the URLs work.

[nilchia]

@Ishikaarora13, congratulations on your first contribution to Galaxy!! 🎉

[nilchia]

@Ishikaarora13
This is the error:

echo 'Tool tools/recount3/recount3.xml not in changed repositories list: .shed.yml file missing'

You need to add a .shed.yml file to the recount3 directory.
You can copy one from another tool and adapt it accordingly to your tool.