Dump: add output format tar and output to stdout (#10376)

* Dump: Use mholt/archive/v3 to support tar including many compressions

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Allow dump output to stdout

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Fixed bug present since #6677 where SessionConfig.Provider is never "file"

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never pack RepoRootPath, LFS.ContentPath and LogRootPath when they are below AppDataPath

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: also dump LFS (fixes #10058)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never dump CustomPath if CustomPath is a subdir of or equal to AppDataPath (fixes #10365)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Use log.Info instead of fmt.Fprintf

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* import ordering

* make fmt

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Matti R <matti@mdranta.net>

vendor/github.com/xi2/xz/doc.go

@@ -0,0 +1,35 @@
+// Package xz implements XZ decompression natively in Go.
+//
+// Usage
+//
+// For ease of use, this package is designed to have a similar API to
+// compress/gzip. See the examples for further details.
+//
+// Implementation
+//
+// This package is a translation from C to Go of XZ Embedded
+// (http://tukaani.org/xz/embedded.html) with enhancements made so as
+// to implement all mandatory and optional parts of the XZ file format
+// specification v1.0.4. It supports all filters and block check
+// types, supports multiple streams, and performs index verification
+// using SHA-256 as recommended by the specification.
+//
+// Speed
+//
+// On the author's Intel Ivybridge i5, decompression speed is about
+// half that of the standard XZ Utils (tested with a recent linux
+// kernel tarball).
+//
+// Thanks
+//
+// Thanks are due to Lasse Collin and Igor Pavlov, the authors of XZ
+// Embedded, on whose code package xz is based. It would not exist
+// without their decision to allow others to modify and reuse their
+// code.
+//
+// Bug reports
+//
+// For bug reports relating to this package please contact the author
+// through https://github.com/xi2/xz/issues, and not the authors of XZ
+// Embedded.
+package xz