Issue #4270: Recursive option for files through API

What does this MR do?

• Adds recursive param to tree API request. With this param we can get all repository paths in a single request.
• Related old github pull request

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Requested in #4270 (closed)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Requested in #4270 (closed)

Added 1 commit:

• 6ff0f24a - Issue #4270 (closed): Recursive option for files through API

Added 19 commits:

• 6ff0f24a...b94f26ce - 18 commits from branch gitlab-org:master
• ddf4f935 - Issue #4270 (closed): Recursive option for files through API

Unmarked this merge request as a Work In Progress

Marked the task All builds are passing as completed

Added 32 commits:

• ddf4f935...3a865ed2 - 31 commits from branch gitlab-org:master
• 3812e15b - Issue #4270 (closed): Recursive option for files through API

Added 140 commits:

• 3812e15b...51087cfa - 139 commits from branch gitlab-org:master
• 9f488c5d - Issue #4270 (closed): Recursive option for files through API

Thanks for picking this up again, @rebecamendez! This looks pretty good to me, just a few questions above.

Added ~164274 ~13884 labels

Added 1 commit:

• 0dacd816 - Issue #4270 (closed): Recursive option for files through API

Added 139 commits:

• 0dacd816...1c4e8663 - 138 commits from branch gitlab-org:master
• e842e7a1 - Issue #4270 (closed): Recursive option for files through API

Added 64 commits:

• e842e7a1...fd1741b4 - 63 commits from branch gitlab-org:master
• 0b75618b - Issue #4270 (closed): Recursive option for files through API

Added 5 commits:

• 0b75618b...faac7121 - 4 commits from branch gitlab-org:master
• 9eb04b30 - Issue #4270 (closed): Recursive option for files through API

Resolved all discussions

Thanks @rebecamendez! @DouweM can you take a look please?

Reassigned to @DouweM