chore: rewrite context.rs with const generics (#104)

* chore: rewrite definitions with const generics

* docs: remove the obsolete one

* feat: define constructors

* feat: define accessors for Input Control Context

* chore: hide the generic `new` associated function

* refactor: define `impl_default`

* refactor: define `inpl_constructor`

* chore: add `must_use`s

* refactor: use range operation

* chore: modifiers return mutable reference to `Self`

For the builder pattern.

* chore: define macros for accessing elements of an array

* fix(macro): wrong order to apply inputs

* refactor(context.rs): rewrite with macros

* feat(`context::Slot`): define accessors

* feat(context::Endpoint): implement accessors

* chore: add `must_use`

* feat: define `slot_state` and `set_slot_state` explicitly

* feat(context::Endpoint): define `EndpointState`

* feat(context): define `EndpointType`

* chore(context): add `must_use`s

* feat(context): define type aliases

* chore(context): implement `AsRef` and `AsMut`

To implement methods on traits.

* refactor: create `context` directory

To define macros in `context/macros.rs`. Traits do not have `.0`.

* chore(context): add macros

* feat(context): rewrite definitions

* refactor: remove unused lines

* chore: add `must_use`s

* chore: add a changelog

* feat(context): implement constructors

* refactor(context::macros): define `impl_constructor_for_bytes`

* doc(context): add

* docs(context): add top-level documentation

* docs(context): use `To` instead of `In order to`

* docs(context): guide to the doc of traits

* docs(context): improve the top-level documentation

* docs(context): add intra links

* feat(context): implement pretty debug print

Author: toku-sa-n

CHANGELOG.md

@@ -9,6 +9,7 @@
 - `CapabilityParameters1::max_primary_stream_array_size` is renamed to `CapabilityParameters1::maximum_primary_stream_array_size`.
 - Bit setter and clearer now return mutable references to `Self`.
 - `extended_capabilities::HciExtendedPowerManagement` is rewritten so that it contains members.
+- `context` module is rewritten.
 
 ## 0.6.0 - 2021-04-27
 ### Added