Modify Vulnerability Management `Tool` documentation

This issue is part of #503371 (closed)

Why are we doing this work

In #503371 (closed) we've removed the Tool filter, and replaced it with a Scanner filter and Report Type filter. To align with these changes, we need to remove the documentation on the Tool filter, and add documentation on Scanner filter and Report Type filter.

Relevant links

• https://docs.gitlab.com/user/application_security/vulnerability_report/
• https://docs.gitlab.com/user/application_security/vulnerability_report/#tool-filter

Verification Steps

1. For the documentation on the Report type filter, go to https://docs.gitlab.com/user/application_security/vulnerability_report/#report-type-filter
2. For the documentation on the Scanner filter, go to https://docs.gitlab.com/user/application_security/vulnerability_report/#scanner-filter
3. Please search https://docs.gitlab.com/user/application_security/vulnerability_report for the word Tool, there should be nothing written on the page on Tool filters.