Merge #93: refactor(async): refactoring async client and minor documentation improvements

1103936 chore(style+docs): style and docs retouch (Leonardo Lima)
442789c chore(style): update new methods style (Leonardo Lima)
565d79e refactor(async): add common GET and POST methods (Leonardo Lima)
31dfa4b chore(docs): minor improvements on docstrings (Leonardo Lima)

Pull request description:

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  ### Description

  It builds on top of #95. Applies minor improvements on some docstrings, and Cargo.toml standard.

  The main change is adding the common HTTP methods for the `AsyncClient`, it removes duplicated code from each Esplora API request, and follows the approach done for `BlockingClient`.

  It makes it easier to extract these methods into an `AsyncEsploraClient` trait (to be done in another PR, initially done here 9cbc387), which the user can implement with any HTTP client of its choice. Also, makes it simpler to rebase and update the `AsyncAnonymizedClient` from #67.

  <!-- Describe the purpose of this PR, what's being adding and/or fixed -->

  ### Notes to the reviewers

  It has some commits from #95, as it builds on top of it and should be merged afterward. Please let me know what you think about the proposed changes and approach.

  <!-- In this section you can include notes directed to the reviewers, like explaining why some parts
  of the PR were done in a specific way -->

  ### Changelog notice

  - Applies minor improvements on documentation.
  - Add common `get_response` and `post_request` methods to `AsyncClient`, previously duplicated through the esplora API calls. It follows the approach done for `BlockinClient`.

  <!-- Notice the release manager should include in the release tag message changelog -->
  <!-- See https://keepachangelog.com/en/1.0.0/ for examples -->

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

ACKs for top commit:
  ValuedMammal:
    ACK 1103936
  notmandatory:
    ACK 1103936

Tree-SHA512: 5579e0cba105f553782e419a16c26fc75b38a2ab8ee523f5ce5e2b9a4560503ef7f81faac546429851802efb66cf125cb36b49f20f088969a6ad580e644d43e5

Author: notmandatory

Cargo.toml

@@ -19,10 +19,10 @@ path = "src/lib.rs"
 [dependencies]
 serde = { version = "1.0", features = ["derive"] }
 bitcoin = { version = "0.32", features = ["serde", "std"], default-features = false }
-hex = { package = "hex-conservative", version = "0.2" }
+hex = { version = "0.2", package = "hex-conservative" }
 log = "^0.4"
 minreq = { version = "2.11.0", features = ["json-using-serde"], optional = true }
-reqwest = { version = "0.11", optional = true, default-features = false, features = ["json"] }
+reqwest = { version = "0.11",  features = ["json"], default-features = false, optional = true }
 
 [dev-dependencies]
 serde_json = "1.0"

src/api.rs

@@ -1,6 +1,6 @@
-//! structs from the esplora API
+//! Structs from the Esplora API
 //!
-//! see: <https://github.com/Blockstream/esplora/blob/master/API.md>
+//! See: <https://github.com/Blockstream/esplora/blob/master/API.md>
 
 pub use bitcoin::consensus::{deserialize, serialize};
 pub use bitcoin::hex::FromHex;