Bugzilla/Notes/14286

bugzilla:14286: local timezone conversion / { {USERTIME}},{  {USERLOCALTIME}} for time formatting / signature time expansion

Add localtime conversion capability to LOCAL{TIMESTAMP,YEAR,...} variable

 * { {LOCALTIMESTAMP}}: current local time stamp in iso-8601 format
 * { {LOCALTIMESTAMP: UTC time in ISO-8601 format }}: convert the specified UTC time to local time stamp

Example
If user's timezone preference is +0900,
 * { {LOCALTIMESTAMP:20080527160000}} --> 20080528010000
 * { {LOCALYEAR:20080527160000}} --> 2008
 * { {LOCALMONTH:20080527160000}} --> 05
 * { {LOCALDAY:20080527160000}} --> 28

Add USERTIME/USERLOCALTIME, the date/time formatting variable

 * { {USERTIME: UTC time in ISO-8601 format }}: format the time according to current user's date format preference, in UTC timezone
 * { {USERLOCALTIME: UTC time in ISO-8601 format }}: format the time according to current user's date format preference, in local timezone (as specified in user's preference)

Example

 * { {USERTIME: {  {CURRENTTIMESTAMP}} }} --> 16:25, 27 May 2008 (UTC)
 * { {USERTIME: 20080527160000 }} --> 16:00, 27 May 2008 (UTC)
 * { {USERTIME}} --> {  {USERTIME: {  {CURRENTTIMESTAMP}} }}


 * { {USERLOCALTIME: {  {CURRENTTIMESTAMP}} }} --> 01:25, 28 May 2008 (XXX)
 * { {USERLOCALTIME: 20080527160000 }} --> 01:00, 28 May 2008 (XXX)
 * { {USERLOCALTIME}} --> {  {USERLOCALTIME: {  {CURRENTTIMESTAMP}} }}

Apply this to default signature expansion

 * --> User123 (talk) { {USERLOCALTIME:20080527162500}}

This will be useful that,
 * the readers will see the signature's timestamp in their preferred timezone and format
 * the signature's timezone and format will be consistent with what shown in revision history