rd3: gui customization needs tweeking for new nav scheme

[ahonor]

Try each of the properties mentioned here and create a screenshot for each place it is rendered.

Try long text strings (eg, ~100 characters).

See also #3671

[jplassnibatt]

Testing options from http://rundeck.org/3.0.x-SNAPSHOT/administration/configuration/gui-customization.html:
01.rundeck.gui.title: works, but long text messes up the gui in login section and left menu (top and bottom)

02.rundeck.gui.brand.html: works, but long text messes up the gui in login section and left menu

03.rundeck.gui.staticUserResources.enabled: works

04.rundeck.gui.logo: partially works, if the png name has a capital letter at the begin or after a dot, it won't work, for example test.test.png works; Test.test.png won't work; test.Test.png won't work.
05.rundeck.gui.logoHires: wasn't able to test this hi res.
06.rundeck.gui.logo-width: partially works, it is on top of the right section of the GUI

07.rundeck.gui.logo-height: works
08.rundeck.gui.paginatejobs.enabled: works, not needed to set it as 'true'

09.rundeck.gui.paginatejobs.max.per.page: NOT WORKING, it always shows 10, I've tried 15 and 5
10.rundeck.gui.titleLink: works

11.rundeck.gui.helpLink: works

12.rundeck.gui.navbar.background: NOT WORKING

13.rundeck.gui.realJobTree: partially working, real tree is not displayed

14.rundeck.gui.startpage: works, I have tried all options, BUT the default one is 'jobs'

15.rundeck.gui.execution.tail.lines.default: WIP
16.rundeck.gui.execution.tail.lines.max: WIP
17.rundeck.gui.enableJobHoverInfo: NOT WORKING

18.rundeck.gui.login.welcome: works, but long text messes up the gui in login section

19.rundeck.gui.login.welcomeHtml: works, but long text messes up the gui in login section

20.rundeck.gui.errorpage.hidestacktrace: works

21.rundeck.gui.job.description.disableHTML: NOT WORKING

22.rundeck.gui.clusterIdentityInHeader: works

23.rundeck.gui.clusterIdentityInFooter: works

[gschueler]

rundeck.gui.realJobTree: let's remove this from documentation/3.0

rundeck.gui.enableJobHoverInfo: needs to be removed from documentation: the job hover info is removed in 3.0

rundeck.gui.job.description.disableHTML vote to remove this as well, this flag was a precaution for admins wary of rendering user html, but the HTML sanitizer works fine.

@ahonor