feat: blobless clone

[Owen-Liuyuxuan]

Basic Info

Info	Please fill out this column
Ticket(s) this addresses	resolves #91;
Primary OS tested on	Ubuntu
Is this a breaking change?	No
Does this PR contain AI generated software?	No;

---

Description of contribution in a few bullet points

• For vcs import, add an optional argument blobless-clone
• In git import:
  • If there is no existing repository, it will perform a blobless clone, then require a follow-up checkout.
  • If there is an existing repository, it will perform fetch with the blobless option.

Related Links:

dirk-thomas/vcstool#283

Description of how this change was tested

• run precommit before committing.
• existing test passed.

Based on the current autoware repos, I run the following commands:

The resulting directory will have a size difference like this, but all required contents exist: