fix: use only internal containers paths (#156)

Description

Define only internal paths in the Database Lab configuration. Don't use relative paths in configs.

A user is responsible for using correct mounts.

Related issue

#156 (closed)

Examples

Config:

...
        walg:
          credentialsFile: /etc/sa/credentials.json

Docker container options:

  --volume {PATH_TO_CREDENTIALS}:/etc/sa/credentials.json \

There are the same rules for dumpLocation, sslRootCert

Checklist

• the MR description has been reviewed
• this MR contains text changes and they have been reviewed OR there are no texts changes
• this MR contains GUI/CLI changes and they have been reviewed OR there are no GUI/CLI changes
• this MR contains API changes, specifications reflect those changes and they have been reviewed OR there are no API changes

Closes #156 (closed)