template overrides: Add override of choose classification page for Browse extension

The format of target variable is not suitable for us - we want to pass
"page.cgi?id=browse.html" as target, but there is then a string like
"?classification..." appended, which will create invalid URI.
template overrides: Modify choose classification page for Browse extension

Now it accepts another variable (parameterized_target) where we can
pass a page.cgi?id=foo.html and have still working URIs.
template overrides: Add override of choose product page for Browse extension

For the same causes as with choose classification page.
template overrides: Modify choose product page for Browse extension

For the same causes as with choose classification page.
browse: Replace all uses of browse.cgi with page.cgi?id=browse.html
describe user: Replace all uses of browse.cgi with page.cgi?id=browse.html
template overrides: Add override of common links template for Browse extension

We will want to replace describecomponents.cgi with our browse page.
template overrides: Use page from Browse extension in common links