Add new Sniff to check declare statements

[jaymcp]

Description

Introduces linting for declare statements.

It will ensure that there is:

• a lower case keyword
• no space between the keyword and opening parenthesis
• one space after the opening parenthesis
• a lower case declaration type
• no unsupported declaration type (i.e. only ticks, strict_types, or encoding)
• one space before the equals sign
• one space after the equals sign
• one space before the closing parenthesis
• no space between the closing parenthesis and terminating semi-colon
• one space between the closing parenthesis and opening curly brace in a block declaration
• no content after the opening curly brace in a block declaration
• a newline before the closing curly brace in a block declaration
• same-column alignment between the declare keyword and closing curly brace

Most of these also come with fixers.

Our expectations:

declare( strict_types = 1 );

declare( encoding = 'utf8' );

declare( ticks = 1 ) {
    // stuff here
}

Changelog

• Add declare statement Sniff

Types of changes:

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).

Checklist:

• All checks pass when running `composer run all-checks.