LIMS-1053: Put synchweb version in footer

[ndg63276]

JIRA ticket: LIMS_1053

Summary:

The MotD is not the best place for the Synchweb version number, so let's put it in the footer. While we're at it, let's improve the look of the footer, using @jlmuir's code from #144

Changes:

• Move Synchweb link to left of footer, site link to the right
• Do the same for both vue and non-vue versions
• Expose $synchweb_version in the api/options endpoint
• Add the Synchweb version to the footer if it is specified
• Add the variable to the example config.php

To test:

• View the footer on any page, check it looks ok
• Check the $synchweb_version is displayed
• Check no errors occur if $synchweb_version is absent