uri: Remove whitespace early when parsing

uri: Remove whitespace early when parsing

For every path/query component, p11_kit_uri_parse() allocates a small
buffer to strip whitespace out.  This patch removes any whitespace in
the URI at the entry of the function to simplify the code.

Note that RFC 7512 actually suggests to ignore whitespace at the
extracting phase rather than the parsing phase.

https://bugs.freedesktop.org/show_bug.cgi?id=97245