Pyexasol

- Fix deprecation warning by setting SSLContext protocol.

- Add hotfix for `lineterminator` change in Pandas 1.5.* ([details](https://github.com/pandas-dev/pandas/pull/45302))

- HTTP transport callbacks are now executed inside a context manager for read or write pipe. It guarantees that pipe will be closed in the main thread regardless of successful execution -OR- exception in callback function. It should help to prevent certain edge cases with pipes on Windows, when pipe `.close()` can block if called in unexpected order.
- HTTP transport "server" termination was simplified. Now it always closes "write" end of pipe first, followed by "read" end of pipe.
- Attempt to fix GitHub action SSL errors.

- [Encryption](/docs/ENCRYPTION.md) is now enabled by default both for WebSocket and HTTP transport. Non-encrypted connections will be disabled in Exasol 8.0.

It may introduce some extra CPU overhead. If it becomes a problem, you may still disable encryption explicitly by setting `encryption=False`.

- SSL certificate verification is now enabled when used with `access_token` or `refresh_token` connection options.
- Updated documentation regarding [encryption](/docs/ENCRYPTION.md).

OpenID tokens are used to connect to Exasol SAAS clusters, which are available using public internet address. Unlike Exasol clusters running "on-premises" and secured by corporate VPNs and private networks, SAAS clusters are at risk of MITM attacks. SSL certificates must be verified in such conditions.

Exasol SAAS certificates are properly configured using standard certificate authority, so no extra configuration is required.

- Added initial implementation of certificate fingerprint validation, similar to standard JDBC / ODBC clients starting from version 7.1+.
- Replaced most occurrences of ambiguous word `host` in code with `hostname` or `ipaddr`, depending on context.