Update "Adding hosts" documentation to emphasize osquery installers (#2956)

- Emphasize generating an "osquery installer" (also referred as "Orbit") using the `fleetctl package` command
- Add instructions for adding multiple hosts and automatically adding hosts to a team
- Remove instructions for generating an enrollment package with the tooling in `tools/mac/`
- Remove the `tools/mac/` directory from the repository because it is no longer used or referenced in any documentation
- Update "Automatically adding hosts to a team" section of "Teams" documentation to point to "Adding hosts" documentation
- Add instructions for migrating from plain osquery to Fleet's osquery installers

docs/02-Deploying/01-Installation.md

@@ -9,13 +9,13 @@
   - [MySQL](#mysql)
   - [Redis](#redis)
 
-The Fleet application is distributed as a single static binary. This binary serves:
+The Fleet application is distributed as a single static binary (or as a Docker container). This binary serves:
 
 - The Fleet web interface
 - The Fleet application API endpoints
 - The osquery TLS server API endpoints
 
-All of these are served via a built-in HTTP server, so there is no need for complex web server configurations. Once you've installed the `fleet` binary and it's infrastructure dependencies as illustrated below, refer to the [Configuration](./02-Configuration.md) documentation for information on how to use and configure the Fleet application.
+All of these are served via a built-in HTTP server, so there is no need for complex web server configurations. Once you've installed the `fleet` binary and its infrastructure dependencies as illustrated below, refer to the [Configuration](./02-Configuration.md) documentation for information on how to use and configure the Fleet application.
 
 ## Installing the Fleet binary
 
@@ -69,8 +69,6 @@ Fleet uses MySQL extensively as its main database. Many cloud providers (such as
 
 Fleet requires at least MySQL version 5.7.
 
-For host expiry configuration, the [event scheduler](https://dev.mysql.com/doc/refman/5.7/en/events-overview.html) must be enabled. This can be enabled via the command line, configuration file, or a user with the required privileges.
-
 ### Redis
 
 Fleet uses Redis to ingest and queue the results of distributed queries, cache data, etc. Many cloud providers (such as [AWS](https://aws.amazon.com/elasticache/) and [GCP](https://console.cloud.google.com/launcher/details/click-to-deploy-images/redis)) host reliable Redis services which you may consider for this purpose. A well supported Redis [Docker container](https://hub.docker.com/_/redis/) also exists if you would rather run Redis in a container. For more information on how to configure the `fleet` binary to use the correct Redis instance, see the [Configuration](./02-Configuration.md) document.

docs/02-Deploying/02-Configuration.md

@@ -807,7 +807,7 @@ The identifier to use when determining uniqueness of hosts.
 
 Options are `provided` (default), `uuid`, `hostname`, or `instance`.
 
-This setting works in combination with the `--host_identifier` flag in osquery. In most deployments, using `instance` will be the best option. The flag defaults to `provided` -- preserving the existing behavior of Fleet's handling of host identifiers -- using the identifier provided by osquery. `instance`, `uuid`, and `hostname` correspond to the same meanings as for osquery's `--host_identifier` flag.
+This setting works in combination with the `--host_identifier` flag in osquery. In most deployments, using `uuid` will be the best option. The flag defaults to `provided` -- preserving the existing behavior of Fleet's handling of host identifiers -- using the identifier provided by osquery. `instance`, `uuid`, and `hostname` correspond to the same meanings as for osquery's `--host_identifier` flag.
 
 Users that have duplicate UUIDs in their environment can benefit from setting this flag to `instance`.