Switch to `fuse_conn_info.want_ext`

[infeo]

... and fuse_conn_info.capable_ext.

Starting with fuse 3.17.0, the feature bitfields capable and want of the fuse_conn_info used during init are deprecated (see https://github.com/libfuse/libfuse/blob/15bb63bbebc7bd11871f60e9c535035e158eb065/include/fuse_common.h#L583-L600). Instead, the new 64bit fields want_ext and capable_ext should be used.

Additionally, to request features with want_ext the inline functions fuse_set_feature_flag() / fuse_unset_feature_flag() should be used. Since these functions only exists since 3.17.0, we have to resort to dynamic function calling (similar to #119).

[infeo]

Some more thoughts:

• We can implement some hacky workaround specifically for Linux, since on Windows and macOS the fuse API is very stable and seldom updated or
• we extend the FuseConnInfo interface with some methods and note this in the javadoc

[infeo]

Development happens in https://github.com/cryptomator/jfuse/tree/feature/capable-ext branch