Update Readme: add info about serialization

[Andrey Kuleshov]

We need to:

• cover in readme missing serialization features
• add examples of serialization (create two sections instead existing one: serialization and deserialization)

[Andrey Kuleshov]

partially added in #157

[Strixpyrr]

I realized in the deserialization example the InlineTable class isn't defined:

@Serializable
data class Table2(
    val someNumber: Long,
    @SerialName("akuleshov7.com")
    val inlineTable: InlineTable,
    val otherNumber: Double
)