[feature] add rate limit middleware (#741)

* feat: add rate limit middleware

* chore: update vendor dir

* chore: update readme with new dependency

* chore: add rate limit infos to swagger.md file

* refactor: add ipv6 mask limiter option

Add IPv6 CIDR /64 mask

* refactor: increase rate limit to 1000

Address https://github.com/superseriousbusiness/gotosocial/pull/741#discussion_r945584800

Co-authored-by: tobi <31960611+tsmethurst@users.noreply.github.com>

vendor/github.com/pkg/errors/stack.go

@@ -0,0 +1,177 @@
+package errors
+
+import (
+	"fmt"
+	"io"
+	"path"
+	"runtime"
+	"strconv"
+	"strings"
+)
+
+// Frame represents a program counter inside a stack frame.
+// For historical reasons if Frame is interpreted as a uintptr
+// its value represents the program counter + 1.
+type Frame uintptr
+
+// pc returns the program counter for this frame;
+// multiple frames may have the same PC value.
+func (f Frame) pc() uintptr { return uintptr(f) - 1 }
+
+// file returns the full path to the file that contains the
+// function for this Frame's pc.
+func (f Frame) file() string {
+	fn := runtime.FuncForPC(f.pc())
+	if fn == nil {
+		return "unknown"
+	}
+	file, _ := fn.FileLine(f.pc())
+	return file
+}
+
+// line returns the line number of source code of the
+// function for this Frame's pc.
+func (f Frame) line() int {
+	fn := runtime.FuncForPC(f.pc())
+	if fn == nil {
+		return 0
+	}
+	_, line := fn.FileLine(f.pc())
+	return line
+}
+
+// name returns the name of this function, if known.
+func (f Frame) name() string {
+	fn := runtime.FuncForPC(f.pc())
+	if fn == nil {
+		return "unknown"
+	}
+	return fn.Name()
+}
+
+// Format formats the frame according to the fmt.Formatter interface.
+//
+//    %s    source file
+//    %d    source line
+//    %n    function name
+//    %v    equivalent to %s:%d
+//
+// Format accepts flags that alter the printing of some verbs, as follows:
+//
+//    %+s   function name and path of source file relative to the compile time
+//          GOPATH separated by \n\t (<funcname>\n\t<path>)
+//    %+v   equivalent to %+s:%d
+func (f Frame) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 's':
+		switch {
+		case s.Flag('+'):
+			io.WriteString(s, f.name())
+			io.WriteString(s, "\n\t")
+			io.WriteString(s, f.file())
+		default:
+			io.WriteString(s, path.Base(f.file()))
+		}
+	case 'd':
+		io.WriteString(s, strconv.Itoa(f.line()))
+	case 'n':
+		io.WriteString(s, funcname(f.name()))
+	case 'v':
+		f.Format(s, 's')
+		io.WriteString(s, ":")
+		f.Format(s, 'd')
+	}
+}
+
+// MarshalText formats a stacktrace Frame as a text string. The output is the
+// same as that of fmt.Sprintf("%+v", f), but without newlines or tabs.
+func (f Frame) MarshalText() ([]byte, error) {
+	name := f.name()
+	if name == "unknown" {
+		return []byte(name), nil
+	}
+	return []byte(fmt.Sprintf("%s %s:%d", name, f.file(), f.line())), nil
+}
+
+// StackTrace is stack of Frames from innermost (newest) to outermost (oldest).
+type StackTrace []Frame
+
+// Format formats the stack of Frames according to the fmt.Formatter interface.
+//
+//    %s	lists source files for each Frame in the stack
+//    %v	lists the source file and line number for each Frame in the stack
+//
+// Format accepts flags that alter the printing of some verbs, as follows:
+//
+//    %+v   Prints filename, function, and line number for each Frame in the stack.
+func (st StackTrace) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		switch {
+		case s.Flag('+'):
+			for _, f := range st {
+				io.WriteString(s, "\n")
+				f.Format(s, verb)
+			}
+		case s.Flag('#'):
+			fmt.Fprintf(s, "%#v", []Frame(st))
+		default:
+			st.formatSlice(s, verb)
+		}
+	case 's':
+		st.formatSlice(s, verb)
+	}
+}
+
+// formatSlice will format this StackTrace into the given buffer as a slice of
+// Frame, only valid when called with '%s' or '%v'.
+func (st StackTrace) formatSlice(s fmt.State, verb rune) {
+	io.WriteString(s, "[")
+	for i, f := range st {
+		if i > 0 {
+			io.WriteString(s, " ")
+		}
+		f.Format(s, verb)
+	}
+	io.WriteString(s, "]")
+}
+
+// stack represents a stack of program counters.
+type stack []uintptr
+
+func (s *stack) Format(st fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		switch {
+		case st.Flag('+'):
+			for _, pc := range *s {
+				f := Frame(pc)
+				fmt.Fprintf(st, "\n%+v", f)
+			}
+		}
+	}
+}
+
+func (s *stack) StackTrace() StackTrace {
+	f := make([]Frame, len(*s))
+	for i := 0; i < len(f); i++ {
+		f[i] = Frame((*s)[i])
+	}
+	return f
+}
+
+func callers() *stack {
+	const depth = 32
+	var pcs [depth]uintptr
+	n := runtime.Callers(3, pcs[:])
+	var st stack = pcs[0:n]
+	return &st
+}
+
+// funcname removes the path prefix component of a function's name reported by func.Name().
+func funcname(name string) string {
+	i := strings.LastIndex(name, "/")
+	name = name[i+1:]
+	i = strings.Index(name, ".")
+	return name[i+1:]
+}