Make parameter-substitution in profiles available

It should be possible to use parameters from a profile as variables for a substitution of the values of other parameters.

Some special variables can be also used for substitution:

• date (in format yyyy-MM-dd)
• time (in format hh:mm:ss)
• uuid (see https://en.wikipedia.org/wiki/Universally_unique_identifier)

Further all environment variables are considered.

Variables to substitute are recognized by:

${...}
%{...}
%...%

You can prevent the substitution with a prefixed backslash where the backslashes will be removed after substitution

\${...}
\%{...}
\%...%

[substitute-test]
source_protocol      = local
source_dir           = ${HOME}/data
log_filename         = ${source_dir}/logs/${profile}-${uuid}.log
cannotsubstituted    = ${foo}

[substitute-test]
source_protocol      = local
source_dir           = ${USERPROFILE}/data
log_filename         = ${source_dir}/logs/${profile}-${uuid}.log
cannotsubstituted    = ${foo}

If a parameter has a variable which cannot subsitute then a warning is logged

possible wrong variable value specified in '<value>' of key '<key>'. not substituted."