Add Parser Debug Print Utility

[AlexanderSinn]

Add option to allow for evaluating Parser expressions for debugging.
Examples:

Input:
parser.debug_print = "10*x + y" "x=[0,9,10]" "y=2"

Output:
Parser Debug Print "10*x + y" = [2, 12, 22, 32, 42, 52, 62, 72, 82, 92]

Input:
parser.debug_print = "plasma.radius"

Output:
Parser Debug Print "plasma.radius" = 0.001

Input:
parser.debug_print = "1000*x + 100*y + 10*z + t" "x=[1,2,2]" "y=[3,4,2]" "z=[5,6,2]" "t=[7,8,2]"

Output:
Parser Debug Print "1000*x + 100*y + 10*z + t" = [[[[1357, 2357],
[1457, 2457]],

[[1367, 2367],
[1467, 2467]]],


[[[1358, 2358],
[1458, 2458]],

[[1368, 2368],
[1468, 2468]]]]

Input:
parser.debug_print = "{plasma.density(x,y,z)}" "x=0" "y=0" "z=0"

Output:
Parser Debug Print "ne" = 2e+20

Input:
parser.debug_print = "
    avg_curr = abs(-8e-9 * clight / bunch_length1);
    head_curr = 0.1e3;
    diff_curr = avg_curr - head_curr;
    a = (diff_curr / (bunch_length1/2)) / avg_curr;
    b = 50e-7;
    ylo = -bunch_length1/2;
    yhi = bunch_length1/2;
    lower = b*(sqrt(pi/2)*(1 - a*z)*erf(((1/sqrt(2))*(ylo - z))/b) + a*b*exp(-(0.5*(ylo - z)^2)/b^2));
    upper = b*(sqrt(pi/2)*(1 - a*z)*erf(((1/sqrt(2))*(yhi - z))/b) + a*b*exp(-(0.5*(yhi - z)^2)/b^2));
    upper - lower" "bunch_length1=1050e-6" "z=[-1.5e-3,1.5e-3,100]"

Output:
Parser Debug Print "
    avg_curr = abs(-8e-9 * clight / bunch_length1);
    head_curr = 0.1e3;
    diff_curr = avg_curr - head_curr;
    a = (diff_curr / (bunch_length1/2)) / avg_curr;
    b = 50e-7;
    ylo = -bunch_length1/2;
    yhi = bunch_length1/2;
    lower = b*(sqrt(pi/2)*(1 - a*z)*erf(((1/sqrt(2))*(ylo - z))/b) + a*b*exp(-(0.5*(ylo - z)^2)/b^2));
    upper = b*(sqrt(pi/2)*(1 - a*z)*erf(((1/sqrt(2))*(yhi - z))/b) + a*b*exp(-(0.5*(yhi - z)^2)/b^2));
    upper - lower" = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1.310698783e-17, 3.532722117e-06, 2.394688371e-05, 2.325514836e-05, 2.256340597e-05, 2.187166359e-05, 2.11799212e-05, 2.048817881e-05, 1.979643643e-05, 1.910469404e-05, 1.841295166e-05, 1.772120927e-05, 1.702946688e-05, 1.63377245e-05, 1.564598211e-05, 1.495423972e-05, 1.426249734e-05, 1.357075495e-05, 1.287901257e-05, 1.218727018e-05, 1.149552779e-05, 1.080378541e-05, 1.011204302e-05, 9.420300635e-06, 8.728558249e-06, 8.036815863e-06, 7.345073477e-06, 6.653331091e-06, 5.961588704e-06, 5.269846318e-06, 4.578103932e-06, 3.886361546e-06, 3.19461916e-06, 2.502876773e-06, 1.811134387e-06, 1.11939185e-06, 8.771348648e-08, 3.017554875e-19, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

• Small enough (< few 100s of lines), otherwise it should probably be split into smaller PRs
• Tested (describe the tests in the PR description)
• Runs on GPU (basic: the code compiles and run well with the new module)
• Contains an automated test (checksum and/or comparison with theory)
• Documented: all elements (classes and their members, functions, namespaces, etc.) are documented
• Constified (All that can be const is const)
• Code is clean (no unwanted comments, )
• Style and code conventions are respected at the bottom of https://github.com/Hi-PACE/hipace
• Proper label and GitHub project, if applicable