[FEATURE] Enhance LDAP/SMTP TLS Configuration and Unify Them (#1557)

* add new directive in the global scope `certificates_directory` which is used to bulk load certs and trust them in Authelia
* this is in ADDITION to system certs and are trusted by both LDAP and SMTP
* added a shared TLSConfig struct to be used by both SMTP and LDAP, and anything else in the future that requires tuning the TLS
* remove usage of deprecated LDAP funcs Dial and DialTLS in favor of DialURL which is also easier to use
* use the server name from LDAP URL or SMTP host when validating the certificate unless otherwise defined in the TLS section
* added temporary translations from the old names to the new ones for all deprecated options
* added docs
* updated example configuration
* final deprecations to be done in 4.28.0
* doc updates
* fix misc linting issues
* uniform deprecation notices for ease of final removal
* added additional tests covering previously uncovered areas and the new configuration options
* add non-fatal to certificate loading when system certs could not be loaded
* adjust timeout of Suite ShortTimeouts
* add warnings pusher for the StructValidator
* make the schema suites uninform
* utilize the warnings in the StructValidator
* fix test suite usage for skip_verify
* extract LDAP filter parsing into it's own function to make it possible to test
* test LDAP filter parsing
* update ErrorContainer interface
* add tests to the StructValidator
* add NewTLSConfig test
* move baseDN for users/groups into parsed values
* add tests to cover many of the outstanding areas in LDAP
* add explicit deferred LDAP conn close to UpdatePassword
* add some basic testing to SMTP notifier
* suggestions from code review

1 files changed, 24 insertions, 3 deletions

diff --git a/internal/configuration/schema/validator.go b/internal/configuration/schema/validator.go
index bd290b91e..a37e3eec5 100644
--- a/internal/configuration/schema/validator.go
+++ b/internal/configuration/schema/validator.go
@@ -10,8 +10,11 @@ import (
 // ErrorContainer represents a container where we can add errors and retrieve them.
 type ErrorContainer interface {
 	Push(err error)
+	PushWarning(err error)
 	HasErrors() bool
+	HasWarnings() bool
 	Errors() []error
+	Warnings() []error
 }
 
 // Validator represents the validator interface.
@@ -110,33 +113,51 @@ func (v *Validator) Errors() map[string][]error {
 
 // StructValidator is a validator for structs.
 type StructValidator struct {
-	errors []error
+	errors   []error
+	warnings []error
 }
 
 // NewStructValidator is a constructor of struct validator.
 func NewStructValidator() *StructValidator {
 	val := new(StructValidator)
 	val.errors = make([]error, 0)
+	val.warnings = make([]error, 0)
 
 	return val
 }
 
-// Push an error in the validator.
+// Push an error to the validator.
 func (v *StructValidator) Push(err error) {
 	v.errors = append(v.errors, err)
 }
 
+// PushWarning error to the validator.
+func (v *StructValidator) PushWarning(err error) {
+	v.warnings = append(v.warnings, err)
+}
+
 // HasErrors checks whether the validator contains errors.
 func (v *StructValidator) HasErrors() bool {
 	return len(v.errors) > 0
 }
 
+// HasWarnings checks whether the validator contains warning errors.
+func (v *StructValidator) HasWarnings() bool {
+	return len(v.warnings) > 0
+}
+
 // Errors returns the errors.
 func (v *StructValidator) Errors() []error {
 	return v.errors
 }
 
-// Clear errors.
+// Warnings returns the warnings.
+func (v *StructValidator) Warnings() []error {
+	return v.warnings
+}
+
+// Clear errors and warnings.
 func (v *StructValidator) Clear() {
 	v.errors = []error{}
+	v.warnings = []error{}
 }