This PR deprecates `CLIENT` api token type in favor of `BACKEND` but
both will continue working.
Also replaces:
- `INIT_CLIENT_API_TOKENS` with `INIT_BACKEND_API_TOKENS`. The former is
kept for backward compatibility.
## About the changes
Follow up on https://github.com/Unleash/unleash/pull/10430 this PR
adapts documentation.
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Co-authored-by: Melinda Fekete <melinda.fekete@getunleash.io>
In some cases, people want to disable database migration. For example,
some people or companies want to grant whole permissions to handle the
schema by DBAs, not by application level hence I use
`parseEnvVarBoolean` to handle `disableMigration` option by environment
variable. I set the default value as `false` for the backward
compatibility.
