SVG cleanup part 1

[vesameskanen]

Various cleanup actions:

• Delete lots of unused icons
• Delete some duplicate icons. There are lots of them left, especially in citybike icons.
• Remove unused css class references from elements
• Use shorter '/>' xml block termination when possible
• Apply svgo cleanup to some icons (removes for example transforms and redundant nested blocks)
• More consistent formatting
• Remove unnecessary xmlns and xlink directives from symbols