Implement few optimizations for reading admin's bot dicts from database
for a constants number of requests:
- add models.get_user_profiles_by_ids() for reading bots profiles
by single query from database
- add models.get_services_for_bots() for reading services for bots
by single query from database
- add bot_config.get_bot_configs() for reading config data for bots
by single query from database
Fixes#8838
load_bot_config_template(bot) parses the <bot>.conf
template file, which can be found in the zulip_bots
package for each bot. It then returns the INI content
of that file as a dict.
Storage limititations are only set on the value of
a config entry, since this is the only user-accessible
part of the schema. Keys are statically set by each
embedded bot.