Make qos serializable

[tot0k]

Hello,

We saw ticket #297 and had already did some related work in our local repo.

Our scope was a bit different: We needed to make the QosPolicyBuilder ser/deserializable, to be able to load it from configuration files, then append/modify QoS Policies before building the QosPolicies struct. It was not a big deal to increase the scope to QosPolicies stuct.

Thus, I suggest this pull-request to resolve ticket #297.

I did not find any contributing guidelines, don't hesitate to tell me if the format doesn't suit you.

Regards,

Thomas

Modification description

• Added Serialize and Deserialize derives to all QoS policies, and to the QosPolicies + QosPolicyBuilder structs.
• Added missing derives to the QosPolicyBuilder for ease of use (Added derives are Clone, Debug, PartialEq, Eq). Its derives now match the QosPolicies ones.

Test Performed

• Built RustDDS with and without security feature
• Ran tests using cargo test -- --test-threads=1, no tests are failing
• Build our internal project using this RustDDS version. I was able to deserialize a QoSPolicyBuilder from a file using serde-json crate.

What was not tested

• Serialization / Deserialization of a QosPolicies (I let @samcarey test in his use case)
• Serialization / Deserialization when the security feature is enabled (We don't use it in our project, so I was just able to compile RustDDS alone.)

Functional impact

One can now Serialize and Deserialize QosPolicies and QosPolicyBuilder using serde.

[jhelovuo]

Thank you. This will be included in the next release.