Tidy up "widgets" XHTML

Add CDATA sections to scripts
Add ALT to image tags and close image tags
DIV tag cannot be inside a STRONG tag, so swap them around
SCRIPT cannot be part of TR tag, so place the SCRIPT inside a TD tag but
hide it.
Teach interface_vip_bring_down() to deal with IP Alias over CARP
Cleanup aliases when temporarily disable CARP, fixes #4116
Merge pull request #1388 from ExolonDX/master
Make logic more visible as suggested by Ermal
Fix up Help links for Inbound Load Balancing.
Update help links for DHCPv6 relay and DHCPv6 Lease Status
Remove old/invalid note
The ID in DUID is Identifier.
See also: ATM Machine, ISP Provider, DMZ Zone, LCD Display, GMT Time...
Fixup the rest of the URLs for DHCPv6/RA help.
Use provided function to change user's password
Point these CARP Help pages at more useful places.
Remove "link", "vlink" and "alink" from BODY tag

This is a positional change to remove "link", "vlink" and "alink" from
the BODY tag, the following themes do not have Anchor tags defined in
CSS, so they use the colours defined in the BODY tag, which is blue
(hex: #0000CC).

_corporate
code-red
metallic
nervecenter
pfsense
pfsense-dropdown

Update "all.css" in the above themes with Anchor tags defined, so that
the colour definition can be removed from the BODY tag.
Add help for Unbound/DNS Resolver and its related tabs.
Some misc updates to pkg help links
Pick up some more new pages for 2.2 that need help links.
Remove some old comments and unnecessary cruft.
Use updated URLs for Limiters and Layer 7 help.
Encode space to avoid rejecting users with spaces in username
Give the proper value for the logging level since even 0 is the correct value coming from GUI.