Feature/search after before on (#9219)

* initial implementation of after, before, on search flags allowing to restrict the search to a specific day or a date range

* missed setting beforeDate in SearchParams in one place

* fixed condition when only flags are used for search without any plain terms

* changed date format used for after/before/on flags to be in ISO8601 format as suggested in PR comments, added a helper function to pad month and day with zeroes allowing the user user either format, with or without leading zeroes

* corrected expected compare to date setting for the TestParseDateFilterToTimeISO8601 test

* fixed a bug for the scenario when you only have the date flags without any terms, added a couple of tests for that scenario

* updated the date filter logic to use parameters to construct the query instead of simply appending strings together, as suggested in the pull request comments

* added search unit test using date flags

* added a helper function to create a test post with a createat date manually set, updated the test for search using date flags to create test posts with different createat dates to be able to better test the functionality

* MM-11817 Add support for after/before/on search flags with Elasticsearch

* add support to search posts to perform the search in context of the client's timezone when filtering by createat date using on: after: before: flags

* updated tests to match the new signature

model/post.go

@@ -96,6 +96,12 @@ type PostPatch struct {
 	HasReactions *bool            `json:"has_reactions"`
 }
 
+type SearchParameter struct {
+	Terms          *string `json:"terms"`
+	IsOrSearch     *bool   `json:"is_or_search"`
+	TimeZoneOffset *int    `json:"time_zone_offset"`
+}
+
 func (o *PostPatch) WithRewrittenImageURLs(f func(string) string) *PostPatch {
 	copy := *o
 	if copy.Message != nil {
@@ -359,6 +365,26 @@ func PostPatchFromJson(data io.Reader) *PostPatch {
 	return &post
 }
 
+func (o *SearchParameter) SearchParameterToJson() string {
+	b, err := json.Marshal(o)
+	if err != nil {
+		return ""
+	}
+
+	return string(b)
+}
+
+func SearchParameterFromJson(data io.Reader) *SearchParameter {
+	decoder := json.NewDecoder(data)
+	var searchParam SearchParameter
+	err := decoder.Decode(&searchParam)
+	if err != nil {
+		return nil
+	}
+
+	return &searchParam
+}
+
 func (o *Post) ChannelMentions() []string {
 	return ChannelMentions(o.Message)
 }