[TASK] Explain 'trustedHostsPattern' configuration option

This patch adds a section to the Security Guide which explains the
configuration option 'trustedHostsPattern'. See security bulletin
TYPO3-CORE-SA-2014-001.

Chapter: Guidelines for Integrators -> Global TYPO3 configuration options

Resolves: #59030
Reviewed-by: Helmut Hummel
[TASK] Document risk of executable binaries shipped with extensions

TYPO3 extensions possibly contain binaries, e.g. Unix/Linux ELF files
(compiled executables). Using these is a security risk, because it can
not be verified what these files really do (unless they are
reverse-engineered or dissected likewise).

This patch adds a section to the Security Guide that explains the risks
and recommends to use binaries from trusted sources only.

Chapter: Guidelines for Integrators -> TYPO3 extensions

Resolves: #59398
Reviewed-by: Helmut Hummel
[TASK] Document Clickjacking attack scenario and defense

This patch adds two sections to the Security Guide which explain the
Clickjacking attack scenario and the defense against it in the FE by
sending X-Frame-Options in the HTTP header.
We also mention that this header is sent in the backend by default.

One section in chapter "Guidelines for system administrators" (web
server configuration example) and another section in chapter "Guidelines
for integrators".

Resolves: #57144
Related: #54201
Reviewed-by: Helmut Hummel
[TASK] Raise version of TYPO3 Security Guide to 1.0.6

Raise version of TYPO3 Security Guide to 1.0.6.

Resolves: #60744
Related: #57144, #59030, #59398