[AboutSystem] Add hypertext functionality for LGPL license

[taos]

Attached is a patch that would add to "LGPL license" the same hypertext functionality that has already been implemented for "MIT license" in the following string from AboutSystem.cpp:

	// Haiku license
	BString haikuLicense = B_TRANSLATE_COMMENT("The code that is unique to "
		"Haiku, especially the kernel and all code that applications may link "
		"against, is distributed under the terms of the <MIT license>. "
		"Some system libraries contain third party code distributed under the "
		"<LGPL license>. You can find the copyrights to third party code below."
		"\n\n", "<MIT license> and <LGPL license> aren't variables and can be "
		"translated. However, please, don't remove < and > as they're needed "
		"as placeholders for proper hypertext functionality.");

As there was some confusion regarding the translation of "[...] %MIT license% .." on HTA due to the fact that % is usually associated with variables that are not to be translated, this patch switches from %[...]% to <[...]> (with the additional benefit of enabling two different hypertext links) - but a change to {[...]}, for example, would of course also be possible.

Unfortunately - in contrast to the MIT license ("MIT") - there is more than one LGPL license: "GNU LGPL v2", "GNU LGPL v2.1", "GNU LGPL v3". So, we would first have to decide which one is "the" LGPL license we want to link to (for testing purposes the patch links to v2.1 at the moment).

[taos]

Adds hypertext functionality for LGPL license.

[anevilyak]

Applied in hrev42956. Thanks!