feat(cache): redis cache (#8822)

# Which Problems Are Solved

Add a cache implementation using Redis single mode. This does not add
support for Redis Cluster or sentinel.

# How the Problems Are Solved

Added the `internal/cache/redis` package. All operations occur
atomically, including setting of secondary indexes, using LUA scripts
where needed.

The [`miniredis`](https://github.com/alicebob/miniredis) package is used
to run unit tests.

# Additional Changes

- Move connector code to `internal/cache/connector/...` and remove
duplicate code from `query` and `command` packages.
- Fix a missed invalidation on the restrictions projection

# Additional Context

Closes #8130

internal/cache/purpose_enumer.go

@@ -0,0 +1,82 @@
+// Code generated by "enumer -type Purpose -transform snake -trimprefix Purpose"; DO NOT EDIT.
+
+package cache
+
+import (
+	"fmt"
+	"strings"
+)
+
+const _PurposeName = "unspecifiedauthz_instancemilestones"
+
+var _PurposeIndex = [...]uint8{0, 11, 25, 35}
+
+const _PurposeLowerName = "unspecifiedauthz_instancemilestones"
+
+func (i Purpose) String() string {
+	if i < 0 || i >= Purpose(len(_PurposeIndex)-1) {
+		return fmt.Sprintf("Purpose(%d)", i)
+	}
+	return _PurposeName[_PurposeIndex[i]:_PurposeIndex[i+1]]
+}
+
+// An "invalid array index" compiler error signifies that the constant values have changed.
+// Re-run the stringer command to generate them again.
+func _PurposeNoOp() {
+	var x [1]struct{}
+	_ = x[PurposeUnspecified-(0)]
+	_ = x[PurposeAuthzInstance-(1)]
+	_ = x[PurposeMilestones-(2)]
+}
+
+var _PurposeValues = []Purpose{PurposeUnspecified, PurposeAuthzInstance, PurposeMilestones}
+
+var _PurposeNameToValueMap = map[string]Purpose{
+	_PurposeName[0:11]:       PurposeUnspecified,
+	_PurposeLowerName[0:11]:  PurposeUnspecified,
+	_PurposeName[11:25]:      PurposeAuthzInstance,
+	_PurposeLowerName[11:25]: PurposeAuthzInstance,
+	_PurposeName[25:35]:      PurposeMilestones,
+	_PurposeLowerName[25:35]: PurposeMilestones,
+}
+
+var _PurposeNames = []string{
+	_PurposeName[0:11],
+	_PurposeName[11:25],
+	_PurposeName[25:35],
+}
+
+// PurposeString retrieves an enum value from the enum constants string name.
+// Throws an error if the param is not part of the enum.
+func PurposeString(s string) (Purpose, error) {
+	if val, ok := _PurposeNameToValueMap[s]; ok {
+		return val, nil
+	}
+
+	if val, ok := _PurposeNameToValueMap[strings.ToLower(s)]; ok {
+		return val, nil
+	}
+	return 0, fmt.Errorf("%s does not belong to Purpose values", s)
+}
+
+// PurposeValues returns all values of the enum
+func PurposeValues() []Purpose {
+	return _PurposeValues
+}
+
+// PurposeStrings returns a slice of all String values of the enum
+func PurposeStrings() []string {
+	strs := make([]string, len(_PurposeNames))
+	copy(strs, _PurposeNames)
+	return strs
+}
+
+// IsAPurpose returns "true" if the value is listed in the enum definition. "false" otherwise
+func (i Purpose) IsAPurpose() bool {
+	for _, v := range _PurposeValues {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}