Convert various README.md files to readthedocs.io (sphinx)

[pevik]

We have various README.md files, convert them to https://linux-test-project.readthedocs.io/ (sphinx).

• docparse/README.md
• lib/README.md
• testcases/kernel/security/integrity/ima/README.md
• testcases/network/README.md
• tools/sparse/README.md