docs: Update mission statement in charter
... to be consistent with FAQ
## Mission
-Enable secure, multitenant, minimal-overhead execution of container and
-serverless workloads.
+Our mission is to enable secure, multi-tenant, minimal-overhead
+execution of container and function workloads.
## Tenets (unless you know better ones)
These tenets guide Firecracker's development:
1. **Built-In Security**: We provide compute security barriers that enable
- multitenant workloads, and cannot be mistakenly disabled by customers.
+ multi-tenant workloads, and cannot be mistakenly disabled by customers.
Customer workloads are simultaneously considered sacred (shall not be
touched) and malicious (shall be defended against).
1. **Light-weight Virtualization**: We focus on transient or stateless workloads
