ShellPkg: Manually parse parameters

ShellPkg: Manually parse parameters

We can't use ShellCommandLineParse as it would error out when the shell was
called with args like "cp -r foo bar", because "-r" is not a recognised shell
option

A different way to avoid some of this manual parsing would be to prepend '^' to
each argument, but that would still require the degree of parsing necessary to work
out which words are part of the command and which are shell options.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Brendan Jackman <Brendan.Jackman@arm.com>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Jaben Carsey <Jaben.carsey@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15220 6f19259b-4bc3-4df7-8a09-765794883524