vulcan-exposed-db check consolidation using Nuclei

[danfaizer]

The goal of this PR is deprecate vulcan-exposed-db check in favour of vulcan-nuclei check by providing custom Nuclei templates. In fact, vulcan-tenable check already report most of the database service exposures but it requires a 3rd party to run and we've decided to provide an open source replacement for the vulcan-exposed-db check instead.

Check changes:

• Update check base docker image.
• Add impact attribute to the Nuclei result struct and assign the value to the ImpactDetail Vulcan report.
• Fix a typo when logging excluded template list.
• Add custom Nuclei template validation and test "detect" tag templates.

Templates added:

• Exposed MySQL
• Exposed PostgreSQL
• Exposed MS SQL Server
• Exposed Redis
• Exposed Elasticsearch
• Exposed MongoDB
• Exposed Cassandra
• Exposed OracleDB