* MM-6839: search relative to executable (#8853)
* MM-6839: searching for paths relative to executable
In addition to searching relative to the current working directory, also
search relative to the location of the binary. This helps locate config
and i18n files when invoking an absolute path to the mattermost binary.
* MM-6839: find mattermost/ binary using utils.FindFile
* add unit tests for utils.FindFile to exclude directories
* fix filtering out directories in FindFile
* fix platform invoking ./bin/mattermost
* MM-6839: searching for paths relative to executable
In addition to searching relative to the current working directory, also
search relative to the location of the binary. This helps locate config
and i18n files when invoking an absolute path to the mattermost binary.
* MM-6839: find mattermost/ binary using utils.FindFile
