Add scratch image

[HansK-p]

Description

This change adds support for the Scratch image. Docker image sizes after a make docker:

iamseth/oracledb_exporter                      0.6.0-oraclelinux_legacy-tablespace   25f1e02b4c1b   6 minutes ago    137MB
iamseth/oracledb_exporter                      0.6.0-oraclelinux                     4e01e343f297   6 minutes ago    137MB
iamseth/oracledb_exporter                      oraclelinux                           4e01e343f297   6 minutes ago    137MB
iamseth/oracledb_exporter                      0.6.0-alpine                          356dfb18f4a0   7 minutes ago    33.2MB
iamseth/oracledb_exporter                      alpine                                356dfb18f4a0   7 minutes ago    33.2MB
iamseth/oracledb_exporter                      0.6.0-alpine_legacy-tablespace        26d2523cd997   7 minutes ago    33.2MB
iamseth/oracledb_exporter                      0.6.0_legacy-tablespace               a76344c6e1f9   7 minutes ago    102MB
iamseth/oracledb_exporter                      0.6.0                                 504e59108b9c   7 minutes ago    102MB
iamseth/oracledb_exporter                      latest                                504e59108b9c   7 minutes ago    102MB
iamseth/oracledb_exporter                      0.6.0-scratch_legacy-tablespace       ccb9b08fa21e   22 minutes ago   25.7MB
iamseth/oracledb_exporter                      0.6.0-scratch                         7107a78ffd8a   22 minutes ago   25.7MB
iamseth/oracledb_exporter                      scratch                               7107a78ffd8a   22 minutes ago   25.7MB

Fixes #438

Type of change

Please delete options that are not relevant.

• [X] New feature (non-breaking change which adds functionality)
• [X] This change requires a documentation update

How Has This Been Tested?

The following was executed in order to test the change

make scratch-image
docker run iamseth/oracledb_exporter:scratch

In additon we have used the image internally for a few days, but with CA and TZ info included. This is mostly as we are running monitoring where TZ info most probably is a requiremt. This has not been validated.

Screenshots (if appropriate):

Checklist:

• [X] My code follows the style guidelines of this project
• [X] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [X] I have made corresponding changes to the documentation
• [X] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules
• [ ] Updated version in Makefile respecting semver v2