feat(docs): add flare smart accounts overview

[nikerzetic-aflabs]

No description provided.

[TheVictorMunoz]

Few comments:

2- fasset-instructions:

some typos:

over-collateralize bridge” → “over-collateralized bridge.”

“hold FLR token for paying gas fees” → should be plural: “hold FLR tokens to pay gas fees.”

Thus, the eradicate completely the need” → “Thus, they completely eradicate the need”

“Deposit an amount of FXRP from you account” → should be “Deposit an amount of FXRP from your account.”

Also, should we add the encoding example for Withdraw (02)?

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3-custom-instructions

“The Flare Smart Accounts is an account abstraction” → “Flare Smart Accounts are an account abstraction.”

“The workflow for Flare Smart Accounts is comprised of the following steps.” → “The workflow for Flare Smart Accounts consists of the following steps.”

“The Flare Smart Accounts allows XRPL users…” → “Flare Smart Accounts allow XRPL users…”

Maybe the "payment receipt is a bytes32 value” piece would be clearer if you included a concrete encoding example...