Readme generator could exclude some files

[crazygao]

Description

Readme generator could exclude some files
exclude examples/flows/integrations/**/README.md since this is 3p integration folder, pipeline generation is not included
Fix a nit in jinja generation
fix flow as a func ipynb description
fix pipeline.ipynb description
Regeneration of all pipelines and README.

All Promptflow Contribution checklist:

• The pull request does not introduce [breaking changes].
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.
• Create an issue and link to the pull request to get dedicated review from promptflow team. Learn more: suggested workflow.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[github-actions]

SDK CLI Global Config Test Result yigao/readme_fix_alter

2 tests   2 ✔️  59s ⏱️
1 suites  0 💤
1 files    0 ❌

Results for commit f2c8606.

[github-actions]

Executor Unit Test Result yigao/readme_fix_alter

557 tests   557 ✔️  49s ⏱️
    1 suites      0 💤
    1 files        0 ❌

Results for commit f2c8606.

[github-actions]

promptflow SDK CLI Azure Unit Test Result yigao/readme_fix_alter

  2 files    2 suites   59s ⏱️
32 tests 30 ✔️ 2 💤 0 ❌
64 runs  60 ✔️ 4 💤 0 ❌

Results for commit f2c8606.

[github-actions]

Executor E2E Test Result yigao/readme_fix_alter

142 tests   138 ✔️  2m 30s ⏱️
    1 suites      4 💤
    1 files        0 ❌

Results for commit f2c8606.

[github-actions]

promptflow SDK CLI Azure E2E Test Result yigao/readme_fix_alter

    2 files    2 suites   1m 18s ⏱️
  57 tests 36 ✔️ 21 💤 0 ❌
114 runs  72 ✔️ 42 💤 0 ❌

Results for commit f2c8606.

[github-actions]

SDK PFS E2E Test Result yigao/readme_fix_alter

  2 files    2 suites   1m 17s ⏱️
  9 tests   9 ✔️ 0 💤 0 ❌
18 runs  18 ✔️ 0 💤 0 ❌

Results for commit f2c8606.

[github-actions]

SDK CLI Test Result yigao/readme_fix_alter

350 tests   337 ✔️  9m 11s ⏱️
    1 suites    13 💤
    1 files        0 ❌

Results for commit f2c8606.